Apparently, yes and two. And to answer DC2, Birmingham have signed a Dane, Tobias Thomsen, as an asset (probably because of this rule) without him riding for the team.
When he rode for Birmingham in 2009, he was obviously headed for the top: he was faster than Jason Lyons, and not many could say that. But then he was injured ... I hope that he has decided to retire now.
My point, which I thought was obvious, is why anyone would go over 70 miles, an hour and a half each way, to Swindon when there is a track just down the road?
Ours (now sold) had a proprietary cover with 'Ashtec Eng.' on it. When it got too shabby, I bought a black plastic one to replace it when the engine was rebuilt (black mainly because I thought is looked more flash!).
We changed the oil after every meeting, but this was in amateur/MDL level.
He rode in all three leagues last season. He shouldn't have any difficulty in finding a Championship place; in any case, it is time that he left the NL behind.