Allowable expenses on rental property

Hi all

As some of you will know I'm not an accountant. However, I thought it might be worth tapping into your expertise here, hope you won't mind.

I'm currently planning to remortgage and rent out my own property and will then buy a new property with my partner. I'm working with an IFA to find a good mortgage rate etc although I think I'm looking at an interest-only mortgage as it's the best way to make the maximum amount from the rental income. Interest-only makes me nervous but I'll still have lots of equity in the house, even after I've remortgaged.

I'm aware that I'll have to complete a self assessment tax return next year to declare the income and I've been reading up on allowable expenses. My questions are:

1. As it's likely to be an interest-only mortgage does this make it an allowable expense? Can I deduct the whole amount when I do my self assessment?
2. If I go for a property management arrangment with a local estate agent every month is this figure also an allowable expense?

These queries are probably dead simple but if anyone can clarify I'd be really grateful. (Tried HMRC this morning but got bored waiting for their call centre to answer the phone!)

Many thanks

Jenny