Far more promising than my Rely from Kevin Stewart MSP as below, But if Murdo Frasers not successful I will hassle him some more!
..........The Scottish Government will consider historic vehicles as part of the development of regulations for the LEZ section of the Transport (Scotland) Bill. Full details of exemptions will be laid out within the accompanying regulations as opposed to the Transport (Scotland) Bill itself................
Well that's promising, it didn't make sense not to consider historic vehicles, but I haven't seen anything that intimated they were to be considered - maybe it's on a checksheet of things to be discussed before the final reading. "Trains - check, Buses - check, trams - check, classic cars - oh hang on we forgot about them"