VENTED 10L Undersink electric Water Heater + Mixer Tap 10 Litre Non Pressure

First off, the install instructions are beyond a joke - there are none, just a drawing of what it should look like when installed, even my pet plumber was gobsmacked.The taps are a different make, and the "A", "B" and "C" markings on the tap DO NOT match the "A", "B" and "C" markings on the connecting pipes; having followed the assembly instructions, I found I had to take it all apart and figure out the correct layout from looking at one of the illustrations.Why on earth they are all 3/8" connections is also beyond me; very few people would be able to locate the tap and boiler close enough to avoid using extra pipe, and trying to get 3/8" isnt that easy, only a few fittings available, and none that met my requirements; I ended up with 15mm adapters and pipes in the middle.Next up, in big bold print it says NOT MORE THAN 6 BAR; with tonnes of dire warnings; then they helpfully provide a 7.5 bar safety valve.Final and biggest issue; I cannot tighten the fittings into the back of the boiler - they just spin - and leak (obviously).After 10 hours of trying to get it to stop leaking, and the same number of TGN attacks from the stress; I have given up for the night. Since the supplier isnt answering his phone, I will rip the damn thing apart tomorrow, and if I cannot get the inlet/outlet pipework to tighten, and stop leaking; Amazon will be shipping it back in tiny pieces.UPDATEMy plumber managed to break one of the brass connectors, so I ripped the boiler apart and replaced it by drilling and tapping the plastic block it is attached to; I now have a 15mm connector - which not only makes life easier - BUT IT DOESNT LEAK, unlike the remaining 3/8" connector.If you rip off the blue and red rubber "things" that hide the oval entry holes, you will see there is a very thin flat spot on either side of the fitting that was hidden by the rubber; you can use this (with a suitably THIN spanner), to tighten the exterior pipe connections.If you can position this so the taps can be directly connected, you shouldnt have this issue - as long as you use the two washers hidden away in a plastic bag with no indication of what they are for; however, for the rest of us, or those who dont want to lose 1/2 a kitchen unit, be very wary; unless like me, you are a professional bodger (AKA maintenance tech).Now it is working, a product review.The case is very thin ABS, even if it had mounting holes, I would be wary of wall mounting for fear of the plastic cracking and the whole thing falling off of the wall; I assume the over sink version has some type of mounting bracket supplied.The interior is almost entirely plastic; with the exception of the electrical components and the brass pipe outlets, the tank is plastic, and it is surrounded by a 2 piece shell of polystyrene, which acts as an insulation material, as well as keeping the tank in place.The heater element is at the bottom, and the cables are left loose across the top of the insulation, going up to the controller at the top of the heater; there isnt really anything else to say; it is a very basic set up made cheaply; however its very basic'ness means there is very little to go wrong, so as long as the heater control is OK, it should be reliable - the element is very easy to change, and even if W.B wont supply a spare, it looks like other small immersion elements should fit quite nicely.