=SUMPRODUCT(--(W2:W31="TS"), --(Y2:Y31="B"))+SUMPRODUCT(--(W2:W31="TS"),
--(Y2:Y31="D"))

After trawling the pages of Messr's Mcgimpsy and Pearson and others the
fromula above works perfectly but I can't believe it needs to be that
complicated.

Simply it looks for occurences of TS in Col W2 - W31 and if there is a
corresponding value of B or D in column X it counts it. Please tell me that
it can be simplified.