any machine shop will put new guides in as they are standard parts and will need to be reamed to fit the valve.
get the valves from motoward, granbys, fosters motomax in UK, the valves should still be listed.
part # 1mo-12111-00 inlet
part # 1mo-12121-01 exhaust
when you get your valves take em to the machine shop to get the guides done.