Is it really that much of a problem?
RAF will have some 136 in front line service - assume it buys 170odd - that leaves enough for an atrition reserve. If FOAS comes in at 2012 as is being mooted (according to Janes Defence Weekly) then potentially JSF will fill the gap anyway. I don't think its that bad a loss is it.
Now waiting for WEBF to spout on how we can use the money saved to restore the SHAR