That certainly looks very nice to me mate.
Instead of the Blue Tac, why not glue a wheel chock to the base and glue the wheel to the chock? That should stop it rising up.
Or, if you have to remove the model from the base for transportation, make a wheel chock from lead, glue the wheel to it but don't glue the chock to the base. It might be heavy enough.
Just a thought...