The first Weslake was raced not in speedway but on Oct 20th, 1974 at Lydden, a grass/chalk surfaced track by Don Godden.
The Hagon Shocks showroom has one the last complete factory bike Tig perry was involved in, a SOHC laydown grasser as raced by Martin Hagon. Two bikes were built, Lee Cross had #2 and crashed it. I have the engine from #2 here in California after being re-built at Antig.
Antig still have spares for the Weslake, and when I was there new engines too.
Go to my website too see a new engine and a laydown pushrod owned by David Perry.
http://xtremesport.org
Weslake today
http://home.adelphia.net/~aeroengine/Weslake.html