i think i did mention before but if they take the teeth off past gum level, very often in cats the roots cause no further pain and problems, they seem far less likely to have problems than dogs and certainly humans. If the pdsa has up to date equipment such as electric drills with different bitts then that procedure would be very quick. whereas gouging out healthy teeth will be prolonged, very painful, more tricky etc etc.
I would do abit of reasearch and speak to a few different vets about roots being left in cats and what they thought of the procdure suggested to leave them. if the pdsa said they would do that then i'd consider it.