Yes, Westwoods were made in the 70s . Not sure how far back for the tractor shaped ones but they were definitely around pre 80s. I had a Lawnbug early 70s or even late 60s!!!!
We used to see the trans drive belt dropped off the big pulley on the top of the trans and used to fit a peg keeper down from above just to stop it falling clear of the pulley when de-clutched.
Did you post this query somewhere else a while back? In answer to whoever did I posted the part numbers for two pulley mod kits for the "zig zag pulleys that did the de-clutching. I'll dig them out again and add them to this post.
EDIT
3230 and 5823 Both on our stock file as "idler pulley mod kits" .Obviously meant something back in the day but may have no relevance to your question!