long term visit visa for parents

[muditmalhotra]

My parents  are senior citizen. They  have two children ( son and daughter) both are married and are citizen of UK.

My mother`s  brother is also citizen of UK.
My  mother`s sister and brother are citizen of Canada. They  have already travelled to UK 7 times and Canada 4 times since 1988 on visitor visa and have never extended visa.

Their  previous stay in UK has been in the range of 1 to 3 months on any one occasion. Since now they are both senior citizen and retired they  intend to visit UK at their  will to meet family of  Son,Daughter and Brother-in-Law .

At times when they go to Canada they also make programme for stay with us in UK because UK is on the way to Canada.  With this in view this time they intend to apply for 2 year long term visitor visa for UK so that they  may not have to run to British High Commission in Delhi for Visitor Visa time and again.

They are  confused what specific reasons should be mentioned in  visa application so that High Commission in Delhi are convinced and their  application is not rejected. I would highly appreciate if somebody who has knowledge and/or obtained 2 year or 5 year visitor visa for UK could advise me reasons to be mentioned in the application. I shall be grateful for the advise.