TPW,
I'll be blunt. There are relatively few RW TP jobs available and several highly experienced and motivated graduates every year from the 'recognised' military flight test centres (such as ETPS, Pax, Edwards and EPNR) - therefore your chances of employment are vanishingly small IMHO. If the military is 'not for you' then your best chance would be to find an engineering job within a major defence company and hope they agree to sponsor you through a course such as
ITPS. If it's your own money, consider a loan and do the
ETPS FTE course. Either way, prepare for hard work and no guaranteed returns - your lack of military background will likely count against you.