Mr. Thom has been dead for many years, so current editions of the books in the series named after him have been written by different authors (and almost certainly by two or more different people).
I have no idea whether Mr. Pratt is still in the world of the living or who actually writes his book series; (anybody know)?
The most recent editor of the UK-version Trevor Thom books was Peter Godwin, the CFI of Bonus Aviation up until when they went bust about a year ago.
Jeremy Pratt was looking well when I saw him about 2 months ago. When not writing books, he's managing director of AFE - the flight equipment and publishing company.
Rather than chase around looking for obsolete books I suggest you subscribe to an on-line question service. I never used these for PPL; (I originally did my PPL in 1960), so I can't tell you the names and web addresses of the on-line question banks but I am sure others will be able to. I would imagine these will be much better for a current student than the confusers.
CATS (Cranfield Aviation Training School) do free online PPL material, presumably in the hope that everybody will be so impressed they'll stick with CATS when they then do their CPLs or ATPLs. I've not seen their PPL material, but I did my CPL groundschool with them and was fairly impressed.
G