Just a quick update re. the work to fix my sunken valve seats etc. The garage called me today and it turns out the head is cracked between the valve seat and the spark plug
They are going to weld the head (apparently it will be like new) and replace all the valves and guides plus a new cam chain rings etc and gaskets and a few other parts i needed to rebuild it, total cost is expected to be around £800 for everything
On the upside at least the barrel just needed a hone and new rings
It is a lot of cash, but, I'm just thinking that at least I'll know that everything is sorted on it then and fingers crossed once It's fixed it shouldn't need to be done again....