[AllanG]

the temperature is reading a pretty cold -2507.9 degrees and 4071.3 for humidity!!

That looks like a reading where there is actually no reading. I take you changed the Sketch back for a DHT22 type?
If so I'd suspect it's faulty. Got a spare?

Note that these don't tolerate being wired up incorrectly, even for the briefest moment.

Yes, I altered the configuration to DHT and was also very careful with the connections so nothing wrong there. Having looked at the circuit diagram the data pin's directly connected to Nano pin D9 so there's no other components that could cause problems. I've also substituted another Nano but still the same, so I too suspect it is a faulty DHT22 but good to have that confirmed. Unfortunately I only ordered the one so no spare.

I'll contact the ebay supplier and ask what they're going to do - and how quickly......!!

Thanks again for the help and support.

Allan.