I use Letsure for my insurance, and you can also get an insurance with them that covers you if the tenant doesn't pay up. Their website is here www.letsure.co.uk
You must ensure that the deposit from the tenant is put into one of the new deposit schemes, and that you've told you mortgage provider what you are doing and that you have their permission to let.
My agent advised me not to leave any white goods, so I didn't (I needed them in Belgium) and to let unfurnished. My house has been let for 18 months and so far, so good.
I go back once a year to see the house and see what needs to be done to it and feel sad that I don't live there, but I know I'll be going back one day.
You can write off mortgage interest, the insurance, the agents bills, some repairs, the electrical and gas checks, and if you pay thectax and the water rates you can do those as well, against any income from the property. The ideal is to have less in rent than you pay out, so you pay no tax. My mortgage is paid irrespective of the rental income,(don't need the rent for the mortgage) so I make a loss on paper, and have enough money available to do things to the house. You'll need to fill in a tax return each year, and if you are going abroad you need a certificate from the non-resident office to say that your rent can be paid gross (you pay any tax due when you put your tax return in).
Hope that helps!