In my A10 from 30-12-17 to 15-6-22 I used a Motobatt MB9U, AGM, 11Ah, CCA 140, L: 136mm x W: 76mm x H: 133/158mm. 2 yr guarantee.
Since 15-6-22 I'm using a Powerline YB9-B, AGM, 12V, 9Ah, CCA 95, L: 136, W: 76, H: 139. 1 yr guarantee.
I found both good. The Motobatt started to loose its charge fairly quickly at the end, but lasted 5 1/2 years.
I also have 6v Powerline in my Velocette LE and it amazes me how minute voltage is lost over a period of weeks without any use. Strangely the 12v one in my A10 loses more - but still good.
I opted for the Powerline because I prefer the nut and bolt connection arrangement, as opposed to the connectors on the Motobatt.
Rog