I've been using Netcetera for the past 3 years, £11 a year which includes 10 accounts, also ask them about Greylisting which is how I found them originally.
Support is also very speedy if you need it but you have to log a ticket before you call (it's a freephone but won't allow you to proceed without putting the reference in)
Virgin (ADSL) => Namesco => Newnet => O2 => Plusnet => Zen => Newnet => Zen => Freeola => Vivaciti (using O2 Wholesale DSL) => Xilo (C&W Wholesale) => Xilo (O2 Wholesale) => Xilo (TT Wholesale due to O2 Wholesale closure) => Zen LLU => Zen FTTP (39.5 Mbps down, 9.5 Mbps up)
Router: Fritzbox 3490
Note: I don't lay turf for anyone. astro or otherwise, all views and opinions expressed are my own based on experience.