Just to bump an old thread...when moving a site from Apartment 10 earlier today, I noticed their own site (http://apartment10.co.uk/) is down, and they appear to have let their domain expire on 18th March (https://www.nominet.uk/whois/?query=apartment10.co.uk).
If you have a site with them, back it up ASAP with a view to moving it as it looks like they may be pulling the plug....