No, no wales accommodation sorted yet, although I have resolved to try and finalise it within the next couple of weeks. I have an irritating entourage of family who say they want to be included but then won't commit to being able to come. Happy to be put in touch with your mate to see if we can sort something out.
I don't have a more recent photo but this is the set up I used at IMAT, and is very similar to the set up I used at Henley. As you say, essentially I fill 1 bottle with concentrated energy drink syrup and then dilute it in my stomach as I ride. I don't remember exactly, but I think the plan at Henley was to drink 1-1.5l water an hour, and because the aid stations were c. 30km apart that meant I needed to collect 2 water bottles at each aid station. That means I need space for 3 bottles for drinking at all times. Then, because I don't have any fancy integrated storage, I put my toolkit and spares in another bottle behind the saddle.
I'm just trialling a couple of other options for Wales at the moment, but no matter which way I cut it I still end up with bottles all over the place.