Ok - to rent it out you will have to pay for an EPC (but presumably you have one for the sale anyway; a gas certificate (if you have gas) we didn't; and an electrical certificate. You can write off against your rent any interest on your mortgage; the buildings insurance; any work you have done on the house that is to repair/replace worn out stuff (I claimed £5k when I had mine redecorated as I had lived in it up to the point it was let; any agents fees; the electrical certificate; I've claimed for having windows redone; boiler servicing; the tree surgeon; the chimney sweep etc, and I pay no tax at all on my gross rent. Any loss you make is carried forward and then offset against the rent the following year before you take off the mortgage interest etc again.
Renting your house out is not scary - I've been doing it for two years without major problems so far, and mine is a large old house.
As for the deposit scheme, your letting agent will sort all that out for you.
I don't have dogs in my house as we have two patios and no garden, and although we are within easy reach of the fringes of Dartmoor, I think it's unfair for a dog to have nowhere to go. I do allow cats however.
I am lucky however in that the rent is not needed to pay the mortgage and goes back into the house to improve things for when we live in it again; or for maintenance of the house.
Weekending is your other option; dh worked away from Monday - Friday for 4 years and came home at weekends from wherever the RN had sent him. We did six weeking from Brussels for 2 years, so it is doable, but I can understand that you don't want to leave your baby.
I would be inclined to rent yours out and rent where you are going until the markets steady. I think (and I'm looking at it from Brussels, but keeping an eye on property prices in the UK,) that a lot of this seems to be media driven and because they predict doom and gloom everyone believes it. It's like an ever decreasing circle. Then again, I've always bought my houses as homes rather than to make a profit on them - I've had the one I rent out for 16 years now, and have no plans to sell it much before I'm 70, so another 28 years to go. Hopefully, the Navy will send us back before then!