Charlestaylor, I would echo Loco's comment, Jet2 have been pretty ex-mil friendly over the last 5 years. So stick with applying to them especially. Eastern, Flybe and some regionals will be/are looking at taking on F/Os but its a long haul process and takes some of the recent recruits there 18 months or more to make the contacts, get the cv to the right person at the right time, sit in a hold pool before starting. The Mil side of things should at least have taught you to have a back up plan, especially as the UK and Europe is in a perfect economic storm. If you have that atpl, hong kong and the east do have opportunities just check on the requirements.
Many of the chaps I know took several years to get a foot in the door as an F/O after a career change, military experience or not. Get connected is the best advice, network. If you can manage it or want to, have you considered flying instructing to keep current/flying.
All the best, need to polish the visor, got some night racing ahead.