Hi Kynan, and a warm welcome to the forum. Its great to have another Scott Bonnar owner on board.
Unfortunately Jocks has not visited the forum since late last year, perhaps send him a PM or email.
Re: your question on the ring gear, this is not the correct forum for questions on your SB590....I will move this thread to: Repairs and Maintenance >>Scott Bonnar Cylinder Mowers.
I will answer your question there....this keeps the archives intact for future reference.
I will now close this thread.
Please do not PM me asking for support. Please post your questions in the appropriate forum, as it helps all members, not just the individual member.
Kindest Regards, Darryl