I'm not as knowledgeable about the Parc area of the scheme more CTC but to answer what I can.
- What advantages (if any) will a relatively epxerienced FO have against a low-hour cadet?
You will be more likely to be on a higher pay rate but that's about it.
Not sure on Parc and varies massively due to your flying.
- selection process
Again not sure about Parc.
Most likely Gatwick
Random / Flexible rostering
- Is it true that I may be stand down for low season?
Yes
- What allowances are offered and what do i have to cover my self?
You get £20 night stop on CTC flexi, that's about it
- Pension, loss of licence, medical?
Nope pay for it yourself
- Any other info you deem appropriate one should know before applying
There are plenty of posts on here both in this forum and the wannabees forum that I advise you have a look through.