Gents

So assuming the Mrs has been in the UK for 3 years from entering with an ILE visa, she can apply for Citizenship. Any ideas how long that process takes through to receiving a Brit passport?

Cheers

From Waiting times

All applications for citizenship are subject to enquiries to ensure that the statutory requirements have been satisfied. Because of these enquires, we anticipate that applications may take up to six months to complete. Some applications may be dealt with more quickly and some may take longer, depending on the nature of the enquiries to be carried out.

Our service standards set out how quickly we aim to decide applications for British citizenship. The standard is that we will decide 95% of applications within six months.

See also Requirements for naturalisation if you are married to or the civil partner of a British citizen and How do I apply for British citizenship or another form of British nationality?