new 407 owner

[MINSTER 407]

Hi everyone, I've just bought a 407 and would be grateful for any info re getting her running a bit better. Specifically, she starts o.k from cold but wont re-start once started to warm up. I'm thinking Carter carb's autochoke may be culprit - anyone know anywhere in UK I can source gasket kit for when I strip it down ? Also, anyone know the correct timing for this engine ? Finally, she runs very rich (maybe down to carb again) but what is the ideal octane to run her on (the chap I bought from said he believed it was factory tuned to run on 2 star back in the day) ?
Grateful for any & all input