Upvote:8
Your interpretation of the rule is correct, namely visitors can enter UK as many times as they want as long as they do not stay for longer than 6 months per single visit
.
However, does this mean that if she stayed with us for 5 months and went back home for 1-2 months, she could come and stay for another 5 months?
Yes, that's fine in theory because your friend is not staying longer than 6 months in any one visit. Given that your friend has an entry clearance which is still in force, and that the entry clearance specifies "MULT" (for multiple entry) on it, then it's within the rules.
I heard that it is advisable to spend only 180 day per calendar year in UK and not more, but I could not find that rule in any official UK Home Office documents.
You will not find such a document on the official UK site because there isn't one and it's impossible to prove a negative. What you would find is a denial that such a rule exists. They had to say this outright in the guidance because there is so much confusion about it...
There is no specified maximum period which an individual can spend in the UK in any period such as β6 months in 12 monthsβ. However, if it is clear from an individualβs travel history that they are making the UK their home you should refuse their application.
Source: Visit Guidance 30 March 2015, for implementation on 24 April 2015
The 'catch' is that if the Immigration Officer thinks that the person is trying to live in the UK, then the person will have problems.
The legal foundation for this is found in the Immigration Act 2014 codified into V 4.2 (b) which states...
will not live in the UK for extended periods through frequent or successive visits, or make the UK their main home;
The rule applies to visa nationals and non-visa nationals alike. There is no formula for determining whether these thresholds have been breached or not; this is left entirely for the Immigration Officer to decide.