I've had a bit of a sift through the UK CAA's site. You only need 5 hours in a complex aircraft (Aircraft certified for at least 4 persons, variable pitch propeller and retractable landing gear) for the CPL.
There are other requirements such as cross country etc.
CPL(A) UK
If you look under hours required for a modular CPL, then you see they'll permit up to 30 hours in a TMG (Touring Motor Glider) or sailplanes.
No mention of microlights. So your desire to fly a tailwheel aircraft is fine, so long as it is classed as an aeroplane.
