To check the cable (T&E) chances are you'll have to go up in the loft and measure the cable. Google your shower make & model number to find out the rating if you don't have the manual. Assuming someone hasn't fitted a higher rated one already.
Yeah, 9 - 9.5 max. Trouble is you probably have 6.0mm T+E from that to the shower. I would be looking for 10.0mm for a higher rated shower. Don't take risks - nothing worse than your house burning down when you're in the shower (embarrassed)
DOM40B6 which i am guessing is 40A so up to a 9-9.5kw is that right? Can you upgrade these to higher? The problem we have is the current shower can't heat the water quick enough but it is a crap titan. This is my first experience with electric showers so not sure what to expect from something like a Mira
Check the rating of the MCB labelled 'shower' in your distribution box.
Thanks, anyway of telling what the supply is capable of? Just moved into a house with an electric shower which is crap. Looking at upgrading before getting a mixer.