It's not necessarily because of where it came from but it is possible something may have been jarred loose inside during the shipment over to you. As i mentioned, Sony Customer Care is only required to service systems sold for their particular region (in your case for the UK).
One other option you may have is if you know someone in the US or Canada ( a relative perhaps) you could send them the PS3 and they could deal with the North American tech support. Once they get the system back they could then send it back to you.