I have to thank my friend Herr Richter in Germany for telling me about second versions of the Commer Film Services Van and Holiday Bus which had actually been there in my catalogue but may have otherwise remained unnoticed. What I presume will be later versions had a centre support bar in the device below the rear bumper.
This was first spotted when he saw the different cut-out section in the camera platform on the Samuelsons Film Service Van. Often these days, the platform and camera have disappeared so you need to buy them separately. Now you know that you need to be careful to get the right platform!
This is not relevant for the Holiday Bus, of course, but that also has the two different versions.
There are, also, different interiors on the 479 model which is known in cream. The 508 appears to vary between cream and white but that may be an effect of age on the plastic.
The cream 479 is pretty rare so you needn't make a space for that but you may certainly now need an extra model of both 479 and 508.
Whilst the Camera Van was available from late 1967 through to 1971, the Holiday Bus had a short life from just Summer 1968 to sometime in 1969. It is all the more surprising, therefore to find the two types of Holiday Bus and it would seem reasonable to deduce that the centre support was introduced during late 1968 / early 1969.
Cast wheels had been around for a while when each of these came out so I am surprised that they are not the normal type found but, as far as I can tell, they're not at all common on 479 and so far I haven't seen any at all on a 508.