Ham Phisted, did you get straight into BA or have you been through other airlines/jobs?
Spent 11 months with FlyBE. Applied to BA as soon as I had their min requirements which, at the time, was 200 sectors on a heavy turboprop. I was 37 when I started with FlyBE and 38 when I started with BA before anyone asks.
PS I didn't do a full UK JAR IR: I converted an FAA single-engine IR to a JAR ME-IR. Don't ask how long it took - I honestly can't remember.