Thought I would update my post to say I managed to source a sump/bash plate from, Burton Bike Bits (www.britishbikebits.com), Part: 82-8819 Engine Sump Guard - BSA B25/B44 / Triumph TR25W 1968-70
Fitted with minor hacksaw and filing modification to clear the right hand foot rest then a little gentle bending to match the curvature of the frame and it fits like a glove.
It has the curved down section at the middle rear end which hooks over the centre stand spacer tube.
Well pleased and it looks the business.
