Thanks Nino...I will be replacing the IDC G.I as well.....

Good to know I was on the right track...Unfortunately PSP is out of both types of BR and RTBB is closed whilst Greg is working very hard at Pinball Expo!

Can these be sourced anywhere else?

It looks like only 1 transistor has ever been replaced.  It is socketed!  Weirdest thing I've ever seen.  The socket is a white plastic one!  I will post a photo when I can!