I'm not too sure why resellers (partners -- call them what you want) insist on prattling on about other parts of their portfolio whenever this question comes up.
Bottom line is that if something goes pfft in Enta or BT land Aquiss (or any other 'partner') are in no better position to get it fixed than another 'partner/reseller'. That's the core issue here. If something goes bang, you're sitting in the middle until either Enta or BT fix it. And your customers are sitting there with no (or limited) connectivity. And my point regarding the nameserver was that if Entanet went, so would Aquiss, along with all the connectivity of your customers. No it's not likely to happen, but stranger things have happened!
The webserver/mailserver staying up when no-one has any connectivity doesn't cut it
Your boss shouting Oi is no different to Jason of UKFSN shouting Oi to be honest which another point I am trying to make.
Great you have some mirrored boxes in two different data centres for redundancy reasons; and so you should. That isn't a valid argument over why someone should pick Aquiss over another partner or reseller for the reasons above.
Now if you decided to sling in your own centrals then you'd be directly in control of all factors. Until such time, you're governed by Enta. At least from a core connectivity point of view. If Boggits decides to turn on QoS all your customers would be affected and there wouldn't be a whole lot you could do about it; just like any other reseller be they UKFSN, Vivaciti or whoever.
Curious as to how/why the bush telegraph got you off a ladder but there you go
