In the recent case of Grijns v Grijns & Ors [2025] EWHC 2853 (Ch) (Master Bowles, sitting in retirement) — the judge made some crucial decisions about costs based upon mediation/ADR and litigation conduct, providing lessons for family property disputes.

What the court decided 

Who “won” and why that mattered for costs.

The defendants (mother and siblings) beat the claim entirely. The son’s only sliver of success — narrowing an account for rent for a short window — was “minor and peripheral” and didn’t sensibly add to trial costs. Result: costs followed the event in favour of the defendants without any percentage deduction for that peripheral point. 

Indemnity costs: litigation conduct “outside the norm”.

The court held the claim was very weak, at points constructed/concocted, and run in a way designed to lever a settlement (including capacity allegations never pursued and a late contempt application that ramped up pressure). That conduct took the case outside the norm, justifying indemnity costs (save for limited post-judgment steps, which were on the standard basis). The court relied on familiar principles (e.g., Three Rivers guidance on when indemnity is appropriate). 

Pre-action incident didn’t justify penalising the winners.

A June 2023 confrontation at the property was lawful on the court’s findings and did not undermine the defendants’ costs position. 

Settlement offers: no duty to negotiate with unrealistic numbers.

The claimant’s Calderbank offers (even the lowest) would have transferred ~£900k on a claim that ultimately failed outright. The court rejected the idea that the defendants should be penalised for not “using those offers as a springboard to negotiate”. If the end result is far better than what was offered, there’s no costs penalty for not haggling over an unrealistic proposal (distinguishing authorities like Kiam and Glencore/OMV Petrom in context). 

Mediation/ADR: no unreasonable refusal by the defendants.

Crucially, the court did not find an unreasonable refusal to mediate:

• The defence side actually proposed mediation early (Aug 2023).
• The claimant set unreasonable conditions (seeking to exclude siblings who were defendants and attorneys and had obvious stakes).
• Meaningful mediation “space” vanished once disclosure ran late on both sides and trial loomed.
• Even if refusal might have been justifiable given the claim’s flimsiness (a recognised exception), here there was no refusal at all — and, viewed overall, the defence approach was reasonable.

Accordingly, the court declined to impose any Halsey/PGF-type costs penalty for ADR conduct. 

How the judge framed the ADR law (the quick map)

• Halsey v Milton Keynes: Unreasonable refusal to mediate may justify departing from the usual costs order — but it’s fact-sensitive.  
• PGF II v OMFS: Silence or failure to respond to a serious invitation to mediate is itself usually unreasonable, though not automatically cost-determinative — it’s one conduct factor in the balance.  
• Gore v Naheed: Even where a party does not mediate, it may still be reasonable not to, depending on the case — no automatic penalty.  
• DSN v Blackpool FC: Conversely, an entrenched failure to engage at all can justify indemnity costs — but again, fact-sensitive.  

Practical lessons for family property (and estates) disputes

1) Engage with ADR early — but sensibly.

• Make and respond to serious mediation invitations (even if only to explain timing/attendees/issues).
• Don’t be silent: a non-response can be treated as unreasonable (per PGF II).  

2) Invite the right people to the mediation.

• Where siblings/attorneys are parties or hold Powers of Attorney, excluding them is rarely defensible. The court saw insistence on a two-hander with mother only as “high-handed” and obstructive. Expect pushback (and no ADR credit) if you try to gatekeep attendance.  

3) Create “mediation space” in the timetable.

• If disclosure is sprawling (years of emails/texts), build time after exchange for a proper mediation. If everyone leaves ADR to the fortnight before trial, a judge may accept that there was no realistic window.  

4) Offers must be reality-checked.

• Calderbank/Part 36-style proposals should reflect litigation risk. A claimant whose case later fails entirely cannot complain that the winner refused to negotiate over unrealistic percentages. Judges will compare the final result with the offer.  

5) Don’t run pressure-tactics you won’t follow through.

• Alleging capacity issues then doing nothing; issuing late committal applications you don’t pursue — this reads as leveraging rather than meritorious litigation, and it risks indemnity costs.  

6) Indemnity costs are for conduct “outside the norm”.

• Weak/speculative cases, claims irreconcilable with contemporaneous documents, or manufactured narratives, plus tactical skirmishing, are classic routes to indemnity (see Three Rivers).  

A short “do/don’t” checklist for practitioners

Do

• Send and answer ADR invitations in writing, with reasons for any timing/format limits.
• Propose a full-party mediation in family property rows (include attorneys/trustees).
• Tie disclosure milestones to a mediation window.
• Pitch offers inside the plausible outcomes range.

Don’t

• Be silent in the face of a mediation proposal (PGF II risk).
• Try to exclude key stakeholders from mediation without a compelling reason.
• Make threats/applications (capacity, contempt) you won’t evidence or pursue.
• Expect costs credit for fighting to trial after rejecting offers that look wild once you lose.

Sources and further reading

• Grijns v Grijns & Ors [2025] EWHC 2853 (Ch) (costs/ADR judgment: index entry confirming citation/date).  
• Grijns v Grijns & Ors [2025] EWHC 1413 (Ch) (liability judgment background).  
• Halsey v Milton Keynes General NHS Trust [2004] 1 WLR 3002 (refusal to mediate & costs).  
• PGF II SA v OMFS Co 1 Ltd [2013] 6 Costs LR 973 (silence to a mediation invite).  
• Gore v Naheed [2017] EWCA Civ 369 (no automatic penalty for not mediating).  
• DSN v Blackpool FC [2020] EWHC 670 (QB) (non-engagement can justify indemnity).  
• Three Rivers DC v Bank of England [2006] 5 Costs LR 714 (indemnity costs guidance).  
• Kiam v MGN (No 2) [2002] 1 WLR 2810 (indemnity vs standard; reasonableness of refusing offers).