Cheers. I just looked at the other eco-drive models on Ernest Jones and they were all 42mm too so discounted them. That one is actually £80 at Argos. Saying that, the eco-drive watch I've been wearing today has been running slow which is pretty annoying.
Other Eco Drive models are available, eg this at 37mm:
https://www.citizenwatch.com/us/en/product/BM8180-03E.html