I checked on the use of "UK". For example in:-

1) Wikimedia UK Ltd

2) Wikimedia UK Limited

This should not be a problem.

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http://www.companieshouse.co.uk/about/gbhtml/gbf2.shtml

Extract:

Great Britain or United Kingdom - if you wish to use these expressions as a prefix, or to use 'of Great Britain' or 'of the United Kingdom' as a suffix, then the criteria are the same as for 'British'. If the words are used as a suffix to the name, they are normally allowed without difficulty. Using the initials 'GB' or 'UK' in your company name does not require approval.

Gordo