As my homepage is set to [google.co.uk...] the default IP address I'm sent to is 220.127.116.11. That is the datacentre that does not show my homepage in the SERPs. :(
But there's hope .. I've noticed the 'new' SERPs spreading. The site now appears in Google.ch (18.104.22.168), Google.de (22.214.171.124) and Google.com.au (126.96.36.199) .. but still not in the UK!
It's extremely interesting to notice a fresh cache of the homepage spreading .. as it's bringing with it keyword SERPs that do include the homepage.
Now, if only the UK can 'catch up' with everywhere else!
EDIT: Bizarrely, the site seems to be most perfectly indexed AND ranking when using Google.ru (188.8.131.52).
As it's an English language site which targets London, UK and is hosted in the UK that's odd to discover to say the least.
EDIT 2: How can Google.ch AND Google.ru both resolve to 184.108.40.206?