First thing, don't be put off by adverts asking for experience of specific sectors. Ok, most of your applications for those jobs will go in the bin, but, as long as you can accept that as par for the course, sooner or later you are likely to get through at least to interview with one or two of your applications. The fact that you do have experience + degree (never mind what experience or degree) is putting you in a good position already.
Also, have you gained any experience of managing your own work or, even better, managing others? Bring that to the front if you have: in the sort of role you're looking staff who don't need heavy supervision are highly desirable.
I would suggest getting someone to check your CV before you send it out, when you have a "non-conventional" career background it can be very important to present it correctly. If you're an IET member you could ask for help from the Mentoring service with this. Otherwise ideally you want to find someone who employs engineers / technicians and ask them to have a look.
It sounds like you've got good stuff going for you: a higher level of education than normal for a technician, many years of experience, and a good reason for changing jobs. Just keep applying and don't worry if you get loads of rejections or "no response" - the right job's out there somewhere!
Andy Millar CEng MIET CMgr MCMIhttp://www.linkedin.com/in/millarandy
"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert