Debt collection agencies in the U.K. have all the same legal power as your local street sweeper. I.e none.
If a UAE bank instructs a debt collection agency in the U.K. to pursue the outstanding debt then you do not need to engage with them at all, should you so wish. They may send letters, they may call you, however they are not allowed to harass via phone, text, in person, on social media or by any other means. They may not discuss the issue with your friends or family, work colleagues or anyone else unless you have instructed those persons to do so o your behalf. They may not enter your home unless invited. They may not attend your work for any reason. There are laws governing their behaviour and complaint should be made if any of the above should take place.
If the creditor takes the debtor to court in the UAE and they receive a judgement in their favour then they may then look to the courts in the U.K. for enforcement. Generally U.K. courts will not entertainment enforcement while there is a chance of appeal in the UAE. Only after the appeal period has passed will they then look to recognise and enforce the foreign judgment.
At that point then they may instruct enforcement agents (England) or sheriffs officers (Scotland) to enforce collection of the debt, should no repayment agreement be in place.
These agents have all the powers of the court and can remove items for sale at auction to pay towards the costs of the outstanding debt. They can, and will, enter your home in order to do this.
The key is communication. I would encourage talks between the debtor and creditor to come to some agreement. Token payments until such time as you are able to increase repayment would be looked upon favourably by the court. Don’t bury your head in the sand.
Good luck to all.