You will need to disclose the final period of self-employment in the UK in your 2014/15 tax return which will be issued on 6 April. Don't forget to put the date of cessation of the business in the UK in the appropriate box in the self-employment pages. If you have always run your accounts to 5 April, there will be no overlap relief.
As far as the rental property is concerned, the income from that will remain taxable in the UK after you have left the UK and, assuming it will also be taxable in Austria, you will be able to deduct any UK tax paid on that income from the tax payable in Austria under the double tax treaty between the two countries. You will also be entitled to a UK personal allowance to use against your rental income provided you are covered by one of the criteria here
. The right to a UK personal allowance may change in the future for non-UK residents as you can read here
As a non-resident landlord, you will need to register with the non-resident landlord scheme which you can do here
. You can apply to not have tax deducted from your rental income by the letting agent or tenant on a form NRL1i which you can find here
. There are qualifying criteria. Any tax deducted in excess of your UK tax liability on rental income will be repaid to you. You will certainly need to continue submitting UK tax returns disclosing your UK rental income if you are issued with them by HMRC or you think you have a UK tax liability but have not been issued with a tax return.
I hope this helps but let me know if you have any further questions.