Family Visa For Uk Holiday

I am applying for a family visa for my wife, so that we can have a two week holiday in the UK next year and, of course, not having done this before I have a couple of points;

My wife, as a Thai teacher, is poorly paid – certainly when viewed by western standards, so I will finance the trip. Even though the form asks for her financial details, I will also send my own. Unfortunately my situation is ‘resting’ – I am too young to have a pension and don't have a regular income - I draw on my investments at irregular intervals. I am hoping that as I can show sufficient funds both here and in the UK to pay for the holiday, that will be sufficient (?).

I will print off my (online) banking details, but I want to black-out the account numbers. Has any one else done this?

My sister will be the family member we will stay with, the guidance notes say ‘evidence of family member…’ eg passport, which she doesn’t have.

Would a scan of a UK driving licence (which also shows the address) suffice?

As often there is a wealth of info’ on ThaiVisa, and I note others experiences, in particular the reasons given for refusal. I thought having a marriage certificate would be enough, but I think now I will include a covering letter about how we met, when etc etc.

I would appreciate any thoughts on the above.