Heritage Open Day: The home off the largest mosaic in Northern Europe. Discover the home of the largest mosaic in Northern Europe. On the outside the church is a late Victorian building, which at first glance doesn't look interesting, BUT look again at the outside of the Apse to the front of the building! Then come in and be prepared to have your socks blown off. I know this sounds a bit theatrical, but I am not joking. It should be noted that St Aidan, at one point in history, was in line to be the patron saint of England but lost out to St George ( a person who may not have actually existed?)