There is no proper Revenue guideline in this area
However forum member mathepac works/worked for Revenue so he has posted before that Revenue's opinion here is that all assets have an 8-year tax life so suppose you moved out of your PPR after 5 years, then the F&F etc would still have 3/8ths of their tax life left so you would have €11,250 of Capital Allowances to claim and you could claim €3,750 each year for the next 3 years.
In your case the 8 years are already up so therefore you cannot claim any Capital Allowances
In my own professional opinion, I would get some sort of estimate as to what those F&F are worth now and claim Capital Allowances of 12.5% on THAT figure. Revenue will probably argue that you can't do this but you would have a strong case.
There is now way you could start claiming Capital Allowances on the €30K though, that's just taking the proverbial and if Revenue did happen to pull you up on it they would likely take a hardline stance then and not allow you to claim anything at all.