All done, found a really reasonable Hetas guy who fitted the eBay one I bought and swept the chimney at the same time for £100 which was a really great price. He said the cowl outside is all fine in contradiction to the other guy who wanted ££££s. Just waiting for the gas fitter to install the fire.
Thanks for all the advice as saved me from big problems, I owe you all a drink or 2.
Looking good.
Feedback is always appreciated