Tank is 8 months ish now so time for an update:
In summary .... its all fine, after the inital water tests i haven't bothered checking anything other than temp and ph in ages (months) i assume its all ok as it looks fine! I expect nitrates are high as i feed loads...but coral growth is superb and algae is not an issue - not broke dont fix, etc, etc.
Mechanically all running ok, went to Oz on business for 10 days and the tank was fine with the only intervention being my brother who topped up my RO vat from the master vat at 4 days (i dont store all the RO in the top up in case it all gets added by a faulty switch)
Only really issue was the vortechs which i binned as they are like running a power drill in your lounge - back to streams which are fugly but half the noise.
Oh, and a halide blew its glass and killed a few coral branches with UV before i realised....while waiting for a new bulb the nem wandered up in search of light and is now happily killing about £200 of SPS, like a Blue Planet camera man i am allowing nature to take it's course

(my kids have £5 each riding on the SPS so i'll cover some losses that way)