Did MWS recommend a specific type or brand of sealant, Richard? If not, I think I'd look at something like Sikaflex, they offer a range of formulations.
A tube of
Dowsil 1080 arrived from MWS today Tim and already applied. This Dow Corning product is an oxime rtv silicon sealant with great tolerance of heat, vibration and moisture. In this case it was the black variant to perfectly match original. It cures at room temperature on contact with moisture in the air, 48 hours according to MWS.
