I would be remiss in not contributing here ... AFAIK the first "Thomas" iteration of trains was actually an O Gauge clockwork made by Hornby in 1966... unfortunately they didnt quite secure the licensing in time ! ( LOL)
So it only appeared in one production run before the all plastic bodied version had a "Facelift" literally and reappeared the next year with a plain boiler front
Hornby Percy Set ! ( Black boiler front with inset face )
Annnd the last clockwork O gauge set made by Hornby ... the "Percy" without the face ( red boiler front)