So living in the house for the past month and a bit has allowed me to ease off the pressure a bit and start snagging / finishing some of the details.
I have underfloor heating under the main bathroom tiles but it wasn't working well. Barely noticeable at 40oC !! Turns out the electrician wired in both temperature sensors and it was adding the values together so after Schluter tech support suggested I check - I removed one pair of wires, lo and behold I have a warm floor. Really nice