family visitor's visa renewal

Good day to everyone, I do really appreciate everyone for the kind support this forum has render to my family so far may God bless you all. to my family so far may God bless you all. Please can someone help me? what documents will my mother need to renew a family visit visa to th uk? Will she need to just submit her passport with another invitation, utility bills, my immigration status data page with a completed form and the financial bank statements? or she will only need to submit her passport alongside with a completed application form seen she has been firstly granted six months family's visa that will expire on 02/12/2010, she still in Londo now but will be going back to Nigeria 02/11/2010? But she will like to renew for a two years family visiting visa by January 2011. Any help will be highly appreciated Any help will be highly appreciated. Thanks

See also Can I apply for a long-term visa? and VAT1.5 Frequency and duration of visits.