A property you let out cannot by definition be your principle private residence except in very restricted circumstances where you are sent by your employer to work outside the UK or to another part of the UK too far from your home to commute. You have to occupy the property both before and after your move away, unless your employer moves you elsewhere again.
You will be able to offset certain expenses against your rental income and you can find a good list here.
If you are a British national or you are covered by the criteria on the list here
, you will be entitled to the UK personal allowance to offset against your UK source income. As that is £11,000 and your rental income will be £7,500 per annum, you won't have any tax to pay. However, as a non-resident landlord, you should read the notes on the non-resident landlord scheme here
. As you won't have any tax to pay, you should apply to have your rents paid without deduction of tax by the letting agent or the tenant before the letting has started.
You may have to complete self-assessment tax returns but if your income is covered by allowances, the tax office may not issue returns. However, it is your responsibility to complete tax returns if you do have a UK tax liability, hence the name self-assessment.
I hope this helps but let me know if you have any further questions.