Ok focussing on the pit falls and some worst case scenarios.....can you also afford the maintenance if anything breaks.... the boiler for example.
Other considerations - Landlords insurance, epc certificate to be provided to tenant (i think) , boiler serviced annually by gas safe engineer and certificate provided, if you rent it to more than one tenant (eg students) it becomes a home in multiple occupancy (hmo) which has a tonne of nasties attached to it. Letting Agents will skim their cut off too.
If you can't rent it you only get a certain period (6mths?) Before you personally are liable for council tax payments.
If you tell the lender and fall behind with payments the lender can appoint law of property act (lpa) receivers who can assume control and collect the rent/flog the house for the best market price they can (which could be in the middle of the double dip?)
Don't tell them and they find its empty and your behind with payments they can treat it as an abandonment and skip the whole repossession process.
.....you may also get a great tenant and have no crap to deal with....personally unless your reasonably comfortable with the costs I think its a ball ache!
Oh and fall into any financial difficulties yourself and the government will tell you to take a hike with help on your mortgage payments and your lender is less likely to be sympathetic (because you have 2 properties)
Good luck but think carefully