It looks like a Shay Rotogardener, made by the people who invented the rotary mower called the Rotoscythe. Picture shows Phil Murrell’s collection of Rotogardeners displayed at Ardingly in 2015 with the similar model in the middle. Alternative suggestion would be a Versatiller by Farmfitters.
here’s a link which may be interesting, Charlie…. http://www.bungartz.nl/hist-grunder.html
I can’t claim any credit for this, I just copied the firm’s name into Google. I’ll be putting a small contribution into your collecting tin!
I’m disappointed but the Wiltshire Steam Rally at Oare, Nr. Marlborough is still on at the moment. They have been known to cancel, though, to protect the ground. That one is bicycling distance from here!
It’s fairly easy to get a Villiers Mk25 Book and if you put Stothert & Pitt Vibroll into a search engine you’ll find reprint books on the Vibroll are available too. There’s a video on one at Youtube: https://www.youtube.com/watch?v=Ux-8ZQABS2c this is the ride on version but the back end looks like yours.