Yes, 66934/6-43/56 are all MH based (though some might officially be LH), along with 66719/28-31/34. The X8 is one of the routes they do (but not X9) as well as 46/X46, 78, 79 and 178.
66944-5/53 went to Southampton a couple of years ago, but like you say are now in Wales. 66946-49/51-2 went...