absolutely fantastic news this is. me and my mate have been waiting for a model of this bus for years. and very happy you are doing the latter variants aswell as early, and possibly the similar Park Royal bodywork version to the MCW (?).
I just hope you do all 4 main liveries; origional WMPTE blue & cream, West Midlands Travel blue & cream (80's), west midlands travel grey and blue (approx 1988-1992), and then the final Red stripe version.
There are also many 2nd hand operators who bought these off WMT, some had large fleets such as Andrews of Sheffield, North Western, Merseyline.