Nothing wrong with stat decs as long as you only sign what you agree with and can confirm from YOUR OWN period of ownership, i.e. the probate period, and also make it clear you're signing in your capacity as trustee/executor and not the owner/occupier.
You can't possibly sign anything related to the deceased's period of ownership as you have no idea of what went on in the past when you didn't own it. You'd be relying effectively on "hearsay" of your mother telling you everything.
But, yes, solicitors can be pain just "going through the motions" when their buyers know nothing and havn't asked questions. I think it's the "tick box" culture of using junior staff for "fact finding" tasks, but they've no common sense - it's like a human version of "computer says no".
When my mother died, the buyer's solicitors were wanting all kinds of confirmations as to when works had been done (i.e. age of boiler, woodwork treatment in the loft, certificates/invoices for double glazing, etc). I obviously knew things had been done but I had no recollection of dates, who did what, extent of work, etc., so I gave them the few bits of paper I found in the house and very rough dates/scope of work that I knew had been done, but they just wouldn't let go - despite me saying there was no more paperwork, got a letter back asking for it all again - they clearly hadn't read the my letter/info and let their computer churn out another "reminder" for all the sections unanswered! There had also been a boundary dispute with the next door neighbour at one point, before I was even born, that they'd picked up on somehow (maybe some correspondence in with the paper deeds) - the neighbour was also long since dead and their house sold 2 or 3 times since, so I couldn't give them any info, but they kept hounding me for that too!
The buyers came round to measure up and I apologised to them for not being able to answer their questions, and they hadn't a clue what was holding it up and it wasn't them being awkward asking questions - they said they'd contact their solicitor and they must have done because they stopped pestering me and the sale went through shortly after.