The website is... http://www.usedmercedesbenz-sales.co.uk
I'm using an nginx cluster shared hosting package.
I'm with Fast Hosts
I've enabled load balancing, and a boost service they offer, as well as upgrading to a low contention database.
The site is quite basic and doesn't have a huge amount of modules installed.
It's just extremely slow to load and can't work out why.
Fast Hosts keep insisiting it's fine.