I have seen the J.P. Simplex mowers around the place, Buzacotts sold them.

I think you might be on the money with 'V' for Vertical, all the Simplex's I have seen for Lawn mowers have started with the V, just 2 were VM or VB on upper case and numbers on lower, and the others were V then a number straight after, all on the lower case. Its also interesting that both the V---- engines were in the 8000s

The one that was positioned horizontally had "R" instead of V, the crank was the same as the "Model 2" but the barrel was one piece alloy or aluminium.

I might have to try to make contact with Gearco soon to try and find it, hopefully I don't end up speaking to a robot...

Thanks everyone!

Thanks for reading!