My Catergory B visa expires on 31st Jan 2090. I have been told that if I do a 'Visa Run' before that date and get another 90 day stamp, I do not have to go back to UK until March 2010 and apply for a new Visa. In affect, I have a 15 month Visa. Is this true?

If it is a multi entry visa yes.

If you have a Multi Entry Non B Visa . Yes do a border run just before it expires and get another 90 days.

If you have a Multi Entry Non B Visa . Yes do a border run just before it expires and get another 90 days.

Cheers, yes it is a multi entry. Is this what you do?

Each time you enter the Kingdom on multi entry Non B you will get 90 day permission to stay whilst visa is valid. As said, do a border run just before your visa expires and you will receive new 90 day permission to stay, effectively stretching your visa to 15 months.

Just Enter before 31st Jan 2090 (Janyary 30, 2090)

By the way it's a long visa you have.