While we can understand that their presence in England is a bit of a problem (one branch in all of England!), we found their customer service fairly good. We got an account from overseas (through NAB), when almost no one else would give us an account at all, and what's more, they did it for free, and fast. We had to call them from overseas twice (as the first woman in the call centre was just plain evil, the second was truly sweet)
Our debit cards were waiting for us when we got here. On the other hand, they were Maestro, which isnt nearly as useful as a Mastercard/Visa Debit. Our account manager was genuinely sweet and helpful, (though she did get my name wrong!). We've been using this as our main account for the last 6 week, and had no problem accessing our money. We werent able to use this card to get a mobile phone with phones4u online, as they had somewhat blacklisted clydesdale. hmmm.. All in all, a decent experience, make sure you get the mastercard debit. Would recommend for new migrants.

Terrible communications. Clydesdale Bank tried selling me private banking services before they had even given me a mortage offer (and obviously before I have become a customer). This is actually breaking FSA regulations, as they actually cold-called me even though I am not yet an existing customer. Every time I ask someone to ring me back with information, I am left handing indefinately.

Avoid this company.