Mystery artillery uniform

[michael1]

Can anyone please identify this uniform, he appears to be from an artillery or horse artillery unit though the uniform looks more Yeomanry like but his artillery (or engineer?) status confirmed by the trumpeters badge as worn by artillery and engineers and both the grenade on his arm above the trade badge and the grenade collar badges, but I don’t recognise the cap badge, any informed opinions very gratefully received, with thanks in anticipation