Just a bit of feedback on how this transaction went, from my point of view.
Excellent! Coms from the seller were top notch, right from the off. He went out of his way, to get it in the post asap. The parcel arrived promptly, as described and extremely well packaged. I installed it and (so far) it seems to work perfectly.
In short, it's difficult to see what more the guy could have done. He gets top marks from me and I wouldn't hesitate to recommend him to anybody who is considering buying something from him.