Immigration for US military member

[Dwhitehall]

Hi,
I'm looking for some advice on how to go about beginning the immigration process for my husband. He is in the US military. We met 14 years ago when he was stationed here in UK and we married shortly after. I moved back to the US with him and have lived there ever since, and we have 1 child. My child and I both hold current British passports. My husband will be stationed back to UK for 3 years shortly and after that point will be retiring from the military. We have decided that we would like to settle back in the UK long term. My question is what kind of visa should we apply for and should be we do so whilst he is working here for the military or wait until he retires? If at all possible we would like to avoid returning to the US after we have moved here. Also I work for a US company and will continue to do so whilst back in the UK, I know there are financial support obligations on my part only from what I've read. Will they care that my financial support is coming from the US and also does it matter that it's a joint bank account?

Thanks in advance for your help.