MetalDave @DavecUK I was able to get a video of it this morning, heres a dropbox link:
I did get it to work eventually (and I had to download it), honestly it’s easier to put on YouTube as unlisted!
The pump sounds a bit like it’s running against a blockage, but even then the sound is a bit quiet, definitely not running dry.
Is water flooding out of the expansion valve tube leading back to the tank? If not then you should try a new pump. I should add a little water is quite normal.
ECM won’t really get involved because your warranty is with the Retailer and they should resolve the problem.