Update and musings:
The brewery has not missed a beat. I brew about once a month, sometimes a double brew day. I can knock out 8 x 15L cubes (per batch) and dilute in to the fermenter, I don't really chill as it wastes too much water for my liking.
The only painful thing with the setup is cleaning, if I was to rebuild I would get cone bottom pots and look at a tipping mash tun to empty the grain. I also have some lines where liquid will sit. If I don't flush at the end of brew day with perc then clean water... it stinks. I could definitely add more disconnects to make cleaning easier but it works well and I don't want to restrict flow anywhere.
There is a limit on how much automation is worthwhile... I was going down the path of float switches and automating the entire process from filling the brewery to chilling however it definitely takes the joy out of it.
The heat exchange diameter is about as small as I would want to go on this setup as well. It takes about 30 minutes for mash temp to match the hex return temp, I think this is because of the flow rate coming through the coil. I have a bigger pump I can try to address this but with 3 kids now it makes it tough to find the time to play.
When setting strike temp, I have to set quite low as the heat exchange will be much hotter than target mash temp because of the volume of water in the mash tun + HLT (where the HEX is).
All in all, very happy with the build, I have only had to replace one heating element I blew up by dry firing. It has had 4 homes and I just moved it back to my place after an 18 month holiday at a mates place.
The kegland fill o meter is also an excellent addition to the brew day.