Hi Mike,
This subject was first aired by myself in the July 1999 issue of the SCCGB Ltd magazine 'The Steam Car'
I wrote this, as I too had cars where an MOT was not asked for when re-licensing, the next issue Oct 1999 carried two letters both quoting the regulations which applied to all motor vehicles at that time, the regulations clearly stated that MOTs were required by ALL motor cars below 3,500 kg in weight.
Because some cars were still not being asked for MOTs as late as 2002, Bill Rich as Chairman of the club wrote a letter which appeared in the October 2002 page 42, where he clearly states in the biggest wording possible that all steam cars require an MOT.
I suggest that anyone in doubt should read The Steam Car Club of Great Britain statement which can be found by clicking here:-
MOT Information
Regards, Jeff.