Just another thought - QR's apply to anyone in the Forces - but they have no force on someone who has never served... so W Mitty, Financial Consulatnt , can call himself whatever he wants I think unless & until he commits a fraud
The old Army Act 1955 had such an offence but no-one seems to be able to find it in the current (2006) Act. A quick search of same shows no mention of someone assuming a false rank at all................... even in the Service....... tho' I wouldn't advise trying it on.....