Relative values
We weren't rich, but we did OK. A halfpenny was, however, a usable coin. My father was bringing home £11 pw, £550 pa, in 1953 as a machine tool operator (working all the overtime God sent). The average wage today is £24,000, a 43-fold increase. So your £50 pistons should today cost £2150. But don't worry, Ian probably doesn't read this...and if he does, I'll buy you a pint next time we meet as consolation...
My very first payslip as an apprentice gave my hourly rate as 1/5 15/16p / hr. Then 1/6 1/2p, then 1/10 3/16", over successive years. An' ah were looky...
Technical: if it is having a first rebore at 70,000, then 1) congrats, and 2) consider oversize liners in rebored muffs, because the muffs are all but certain to have lost their grip. Basically it restores the bike to the way it was when it left the factory. It made a noticeable difference to my bike (rebored in 1970 at 43,000 and fitted then with Instaseize Italian pistons) when done properly in 2004 at 50,000, and wasn't excruciatingly more expensive than just a rebore and new oversize pistons.
Tom
Tom