Yes I do have a Toro Overdrive fitted to the 2A.
Big Sandy, the Toro is a Bearmach overdrive so I don't think it's spanish... Anyway, from the very limited information available on this overdrive, it is supposed to be the stronger and longer lasting unit out of the Fairey and Bearmach overdrive(s) that were available for the Series vehicles.
I still need to find out what oil the Toro overdrive takes, but I think it's the same as the Fairey. I've also heard that the Toro internals are similar to the Fairey but are 'beefed up' somehow to make it stronger, and then the larger oil capacity for cooling makes it even longer lasting if kept with the right amount of oil in.
Today I had the 2A out on the roads for a substantial run, about ten to fifteen miles in total, maybe even twenty. The overdrive was engaged about half way through this "run" up on the Pennines after making sure the normal gearbox still operated properly and the overdrive was very quiet to any other LR with an Overdrive I have been in. When engaged it made the gearbox almost silent, and engaged very quietly with the clutch depressed. This is of course being compared with somewhat used and worn Fairey overdrives and I don't know what condition my Toro overdrive is in mechanically...
They are great overdrives. But were only made for a very short period before being discontinued from what I can find out. What I think may have been the case is that Rover chose the Fairey overdrive as the one it recommended because there is also the Fairey free wheeling hubs, while Bearmach didn't have any free wheeling hubs of their own to my knowledge. Plus I don't know what the cost differences were, so Fairey could of had the overdrives and hubs in a deal with Rover while Bearmach only had the overdrive that they could supply. I could be completely wrong on this reasoning though.
Anyway. As a result, there are even fewer of these overdrives in existance because people litterally ran them into the ground. Lack of servicing and maintenance resulted in many having severe mechanical failures, and because it's not possible to get many if any at all of the internal components they are rare to come by in working order. What some people do is get a handful of these units over time and try and build a functional one out of the set of overdrives they have.
My personal opinion is, if you can find a good working Toro, have it if it isn't going to be a fortune compared to the Fairey to buy and maintain it properly. Or alternatively get a Fairey that you know you can get a replacement fairly easily and get parts without too greater difficulty.