Hold fire on a new Tx PCB for a bit Zitron.
I'm building a test Tx rig to fit inside the module case.
I'm going to try it with an Arduino Pro Mini board at 3v3 & 8Mhz (wired 'dead bug' style) as the board will just fit across the Tx module case.
Should make the design simpler if it works out.
I'll post my findings here...
Nigel.