..after much Googling (well, Duck-Duck Go-ing), solved the problem and found a compatible replacement 433MHz sensor for the year 2005/6 model Science Museum SM2282 weather station...TFA Dostmann 30.3139 (got it on Amazon). Bought purely on the premise that the 433MHz symbol was practically the same on both the old and new models. All back up and running and ordered 2 more for the other 2 channels.