The Temperature / Humidity Sensor in my Watson W-8681-PROII Weather Station had recently failed, forum searching for a replacement hadn't provided any results, I also contacted a well known Amateur Radio Retailer, located north of the M25, who advertises Weather Stations but doesn't sell any spares for them.
I had bought a HP2551 from Weatherspares.co.uk previously, so a quick search produced the WH65/WS69 Temp / Humidity Sensor, a email to Adrian at Weatherspares, confirmed that it should work with the Watson unit.
On arrival I plugged the new WH65 into the faulty Watson Wx Station CPU board and it worked OK, when reassembling the Watson unit, I found that the WH65 Sensor 4 core ribbon cable was too short to be installed permanently, so I lengthened it using the old Ribbon cable from the U/S Watson Temp Sensor using a Soldering Iron and some heatshrink.
The Watson unit has now been boxed up and is currently on test in the Garden, prior to re-installing on my commercial site.