Upvote:2
With a Standard Visitor Visa, she can come and go and do any activity listed in Appendix 3 of the Immigration Rules Appendix V visitor rules. This holds true even if the stated purpose on the application now differs from the current purpose. Among them, you'll see
Tourism and leisure
3 A visitor may visit friends and family and / or come to the UK for a holiday.
Of particular relevance, as this question is frequently asked on this site, @GayotFow explained that:
On 24 April 2015 all existing visitor visas, including family visitor, business visitor, student visitor, child visitor, and others were automatically converted to the 'standard visitor visa'.
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The controlling link if you are interested is the Immigration Act 2014.
For additional reference: Can I travel to the UK for business on a C visit visa?