Sounds like someone about to have a birthday - I have another year and am currently considering mounting campaign for all AF to recieve the same fat pensions as MP's however cannot seem to get one of them to support me
Go on to the National Statistics site, get all the RPI increases since the year you left and increase your pension by them and you will get the answer. Don't hold your breath RPI increases have been low these past few years so the increase may not be a big as you hoped.
It isn't possible without working it out, you can do that yourself. If you just want a fugure plucked out of the sky then go for about 40% increase and you wont be too far out. Don't forget that if you fully commuted your pension when leaving you will also have to add your uplift. There are a gazillion threads on how to work it out. A quick search will find one.