Thanks everyone for the nice comments.
The tank is a Fluval 800 Uno and my partner used perspex for the dividers which are siliconed in. We sanded the perspex down so the boys can't see each other!
The tank has a Fluval 305 external filter on it, I know it's a big filter for little fish but it's a lot easier and helps control the water flow. My partner put a false bottom in the tank which has holes in allowing the water to filter right through. The pvc pipe is attached to the outlet and we've adjusted it so there is very little flow going through.
There is only one heater on the left hand side of the tank and it's keeping the temperature at a constant but we are planning on adding another heater just for good measure!
I was worried about the fish jumping over the dividers and I knew it would be a pain for my partner to cut the perspex around the lights. He decided to silicone some more perspex into the lid just below the lights and made a 25mm hole above each compartment so I can feed them without removing the lid. There is a slight gap between the divider and the perspex in the lid but not big enough for them to jump through.
My partner has to take all the credit, he came up with the idea and did all the hard work and swearing!
He did put a lot of work into it and if you plan on making one you are best investing in some clamps for the dividers while the silicon dries. He's my Mr DIY so luckily he had everything to hand that he needed!
Tank was originally set up as a community tank so we had everything we needed except the perspex, but if we were to set it up from new, it would be quite expensive. A smaller filter could be used but the way the tank is set up you need an external filter. Any tank could be adapted within reason but we find Fluval tanks reliable and reasonably priced.
If anyone is interested further and wants to make one, I'll speak to my partner and try to sort something out. Whether you just need help and advice or maybe want one making, PM me and maybe we can come up with something.