Bimbler, I don’t think rank & file MPs are worth that much really
Seems to me:
You need to be able to ingratiate yourself with constiuency activists & get nominated
You need to be lucky enough that the small active group at the head of your chosen party is currently popular enough for you to be voted in
Once in, you need to be able to behave like a schoolkid during debates then do as you’re told by the whips. Oh, and maybe sit on a few committees, plus occasionally show your face back at constituency to hold surgeries (where you hear complaints & pass them on for others to deal with – or not, it’s not like you need to care once you’re seen to pass the buck)