If you are where you say you are in your profile pane; you're about three junctions down the M6 from me.
If you want a second set of eyes on it; and risk journeying so far north, I'd happy have a look, prod & poke, though no expert on Pentax's.
If no joy, can send you away with loan of a Zenith, and meter, that I know works; and has a fresh (Well, ood {out-of-date} 2004 dated Kodak!) film loaded after my daughter abandoned her exploration of film, when her GCSE teacher started setting 'deadlines'!
"Noooo Dad! I need them by TOMORROW!" Or maybe, if we can find many batteries, one of the OM's and one of those spawn of satan 'zoom' lenses
Err... yeah.... it gets you that way! Last week, I decided to have a tidy-up, as when I looked up from my monitor, from where I was sitting, I actually had 10 working cameras in my field of view, and eleven rolls of film! (I can only see five cameras and 8 rolls of film now I've tidied a bit!)