Mine are not the best, but they are not too bad. I can think of lots of Enfields I'd rather have but instead of constantly striving for more, sometimes it's good to be satisfied with what one has...
As new rifle production came to an end, ROF Fazakerley made a run of at least 23,000 new "FTR" Mk 2 rifles in 1956-57 (possibly 1958?). They all lack the cutt off block on the body showing they were new production bodies however not all the parts installed on the rifles were "new", some were seconds or were taken from the real FTR program that finished in 1958. The FTR marking gave Fazakerley a way to get rid of leftover stock new bodies without the need of using all new manufacture parts.
I dug up Charles Stratton Volume 2 Lee Enfield No. 4 and No.5 rifles. According to his book Fazakerley stopped making new No.4 Mk 2 rifles in 1955. They also placed the month of manufacture ahead of the year. Serial number prefix PF from 1948 to 1954:
1948 - PF 22xxx to PF 68xxx
1949 - PF 68xxx to PF 139xxx
1950 - PF 184xxx to PF 223xxx
1951 - PF 228xxx
1952 - PF 231xxx to PF 263xxx
1953 - PF 264xxx to PF 309xxx
1954 - PF 314xxx to PF 376xxx
1955 - UF 55Axxx to UF 55A 21xxx
You have to go all the way back to 1942 to see an 'A' prefix. I'm not sure how a No.4 Mk 2 got an 'A' prefix, at least it's not covered in the book.
This came out of the wrapper. Doesn't seem to match the serial date listing shown. Left over bits perhaps?
Sorry, not trying to hijack the OP's question, just questioning the serial/ date listing.
Interesting, the loop on the trigger guard on a 1955 No4 Mk 2 production.