Some support is in the UK and some is abroad from what I gather. My brother is one of the people being moved to a different call centre due to Bulldog moving support. I know he used to take 1st line support calls, and use to speak to maybe 2nd and 3rd line support in other countries.
Bulldogs call centre is ran by Garlands in Hartlepool in the North East. Garlands look after call centres for Vodafone and other companies, so it looks like most staff will be moved to other Garlands clients.
Pipex really needs to sort itself out. I know they own 123reg.co.uk, and I've used it's support, and after 5 weeks I've still not received any response from 123reg support, seems to have gone downhill since Pipex took over.