The thing is Steve, there is no hard and fast rule, in the rules, to cover this.
It has come up a few times over the years and the answer has always been, if you start with it on, you have to finish with it on.
It appears though, that this rule may have changed and I did not know about it. "hands up, i may have got it wrong"
I will check with Sparky next week when he gets back from holiday.
Somehow I made TEAM ENGLAND 2012 and 2013
Illiterate writer for AirGunner
The real Kung Foo Panda.