The forfeiture of pension is a bit of a myth really. I have taken some for Court Martial, who have been sent down for significant criminal offences, and they have still kept their pension. Pension that you have earned is protected by UK Law and it is very hard to take that away from anyone.
You need to commit treason and go down for 10+ years to even be considered...
https://www.gov.uk/government/upload...regs-clean.pdf