There's a few Dark Blue stories of personell challenging the 12 months rule and stating they would only give one months notice aka the European Courts version of notice vs pay interval if you are without contract, as I believe all commissions are. One corker involved the Naval Provost turning up on the doorstop on day 32 and attempting to arrest the retiree, only to be confronted by his rather large solicitor threatening writs for wrongful arrest, harrasment etc, etc worked a treat!!
Appears that if you fight your corner the agreement is "okay you can go but don't tell anyone else!!"
In fairness 12 months notice does give a decent chunk of paid time for those who want it, if His Tonineness really wants 12 months notice then he should put it in the contract.......
,...........you've all got one haven't you??