The picture above compares the Irregular mounted British general with the two Airfix mounted releases: British hussars and French cuirassiers. The image illustrates the problem with assuming that even figures from the same manufacturer will be compatible. The discrepency in size between the hussars and cuirassiers is well-known. Ironically, the cuirassiers were heavy cavalry, so if anything those figures should be larger than the hussars.
Since both sets tower over the Irregular general, I have added a second image, which puts the Irregular figure on a thicker base. As you can see, even this is not enough to disguise the differences.
Incidently, I don't know who to credit for the paint job on the hussars. They are from a batch I picked up on eBay several years ago. I believe they are painted to represent the King's German Legion. Click on the pictures to get a closer look.