Hi Russ,
If I understand you correctly you need a replacement thermostat housing – the alloy (silver-grey) domed component which is attached by two bolts to the cylinder head. The top hose fits onto the pipe which is integral with the diecasting.
They don’t appear to be listed in club parts, but if you are a member contact John (spares) and he may be able to help. Alternatively try E-bay (the housings were common to anglias, MkI cortinas, Corsairs using 1200 or 1500 engines – maybe crossflows too).
Make sure you use a good antifreeze which will contain corrosion inhibitors to reduce likelihood of future problems.
Andrew