AKS sell the complete kit - https://www.akstuning.co.uk/top-mounts/562-genuine-ttrs-top-mounts.html
When fitting new top mounts, remember there is a correct orientation to use. There should be a little nub on the rubber part that faces inboard or something. Google it as I can't remember......even though I've done them about 3 times now 
The OEM ones have an arrow that should point to the front of the car if I remember correctly.
Yeah that's a good point, they do. They're really hard to see in the darkness of the wheel arch though, so maybe a bit of paint would be better!