Bringing Wife's Child to UK

Hi,

I am a British Citizen by birth.

My Wife is a Russian Citizen with 2 years leave to remain as a spouse.

We both work and claim no benefits, plenty of money coming in, good accomodation etc.

We want to bring my wife's 4 1/2 year old child to the UK to live with us. The father has no objection and is happy to sign that she has sole responsibility for the child. He provides no money and does not support the child in any way. The child is staying temporarily with my wife's mother, the childs grandmother, in Russia.

I know we apply using online vaf4 and then go in to submit evidence at the vac in russia, but please give ANY advice on:

evidence / documents / photos required
how to prove sole responsibility to the ECO's satsifaction
any other points you might think of!

thanks,

never done this before,

thanks again.

See also sole responsibility.