I would be surprised if you actually need to claim it - I would expect the RAF pensions dept to be well aware of your existence and contact you, assuming they know your address.
I seem to recall that you can fill in your application up to a year before you are due to receive your pension. I am pretty sure that I completed one of these forms as I recall receiving the confirmation slip.
Lucky you. My husband served from 1953-1966 and receives NO pension. It is payable I believe after 1978. During his service he was on Christmas Island throughout Grapple X&Y. This, as well is ignored so far by HM Government. Many of these suffered the after effects still.
To be fair, Nannakath, very few employers provided company pension schemes in those days, so the armed forces weren't much different to everyone else in that respect.