I am a little bit in disbelief that you would even comtemplate this, it's not wonder that the UK is in such trouble. You have a house with equity? can you consolidate the debt into the house? If you dont pay them back you risk getting into big trouble if you ever decide to go home do you really want to run that risk? Plus it's not like they dont know where you are since you've used them here and all.
Seek some sensible financial advice, not from a forum, be sensible yourself and take responsibility for your spending. If you could not have afforded to come here you should have waited. Speak to the bank who may be able to reduce the interest or help you somehow. Please do not just stop paying. I have $28k debt here from various reasons and sometimes feel like we are drowning in debt but we will get there paying off bit by bit it will just take a while. You may have to make sacrifices, downgrade the car, stop holidays, cook at home not eat out, live below your means not above but you will get there.