In answer to 'bkdavy' and 'fast sky' questions re fuel tank position, whilst the build manual illustrates the tank almost immediately behind the firewall, regrettably the fact is it just will not pass through the structure of the fuselage to get there - hence it lives directly under the front section of the wing with approx 80% of it in front of TT's C of G point with the remaining 20% behind it .... Thankyou 'sigrun' for the very informative technical case - I shall print off and study at leisure!
This Sunday I will try (UK weather permitting) with rear edge of wing shimmed up approx 1/8" as suggested and hopefully my instructor will not feel the need to become so agitated with either the performance of the plane or its 'ground pilot ...