That's cheap as chip,,good value,,with the extra guarantee its good.There are cheaper makes of boiler but Worcester are the masters of gas. (not oil) You will get the system flushed (sealed system I hope) if not sealed then get it done,its a must. Inhibitor put in,,double it up 2 years on and bobs your uncle.
That seems a good price Red. Our system is Microbore and our boiler is Italian, I forget the name but when we tried to have it serviced the chap refused to touch it as he said it would break and then getting parts would be a nightmare. Anyway its still running 10 years on and we're just waiting for it to fail so we can replace it with a better make. Do Worcester do boiler for Microbore I wonder?