http://www.roverlink.co.uk/products/view.aspx?id=46 Take a look at this here
High temperature exhaust spray paint I have found as good as powder coating as long as the wife
doesn't mind you borrowing her oven and you can do it at home cheaply
Fit a PRT remove the original thermostat and replace it by blanking plate PEL000040 and seal PEF10010 this should fix any thermal shock issues on a 1800 VVC
Leave the head alone unless the gasket has failed
Timing belts can deteriorate with age ,check it and if mileage is high for peace of mind change it
REGARDS PiltV40