ocho gardena,
Interview is the only stage normally, no sim rides or tests in the past. Only three pilot bases in the company LTN, LGW & MAN. As has been said previously your fleet and base will very much dictate your working pattern. If your A320 rated you can expect a busy roster year round especially at MAN. As RHINO wrote the new F/O scale starts on 39k rising to 45k after 10years. The new Captain scale that will apply to new pilots when they get commands starts on 64k and rises to 77k.
Flt allowances very much depend on base and fleet. On average if you're busy expect around £250-£300 per month if your flying is out of your home base, more if on voyage to other bases (if you're on the A320 up north this will not happen!)
No sector pay.