Contributions to UK pension plan

Last year, DP worked for 4 months in the US (until May), then the rest of the year in the UK.  He has a group personal pension plan/defined contribution which both he and his employer pay towards.  The accountant doing his taxes said the employer contributions don't need to be mentioned on the tax return - is this correct?  And what about DPs own contributions, can these be deducted?  Presumably the unrealised gains on the pension pot don't need to be mentioned anywhere? 

DP is going to do the FBAR himself, and will mention the pension on there.

Is the accountant perhaps relying on making a treaty claim on Form 8833?

I don't know, they haven't asked for the details about the contributions (besides asking what type of pension plan it was), they just said they don't need to be mentioned.  Although perhaps they will ask for them later as they haven't actually started doing the return yet.