Todays test drive went very well, certainly less vibration transmitted from than when the partially seized one was fitted. So I'm 100% happy using this and an alternative part.
I will be needing another pair of dampers for the 1600, so I'm going to start a thread for a "Group Buy" to get the numbers, it'll be money up front I'm afraid plus a wee bit for shipping the whole lot to me and then distribution to everyone.
Once I have an idea of numbers I'll talk to the supplier about the level of discount we can get on the cam belt end damper, but it starts at 10 units. Not sure what I can get on gearbox side but they are much cheaper than the cam belt end (£25)