Hello, I am Keith, one of the experts on Just Answer, and pleased to be able to help you with your question.
Firstly, when you moved to HK did you complete a Form P85 and send it to the Inland Revenue as it was then? If you did not you should do so immediately, but of course now to HMRC. Fortunately there is no time limit as to its submission, it is available on the web and can be filed on line. On receipt HMRC will classify you as non resident for tax purposes. Once so classified you can spend up to 91 days in the UK in any one tax year without breaching your non residential status.
However, even non resident you are still liable to UK Income Tax (IT) on your UK rented property income. As an EEA citizen you are entitled to the usual personal allowance (11K this tax year, 10.6K last). Claims for a rebate on any UK IT deducted are dealt with by HMRC's Nottingham Office, NG6 1AB. If your net rental income is below your personal allowance you can ask that office for no tax to be deducted in future.
Always bear in mind that this rental income may be taxable in HK also, but under the Double Taxation Treaty between the UK and HK the same income stream cannot be taxed in both jurisdictions. This is achieved by means of tax credits, the tax deducted in one country being allowed as a tax credit against any liability in the other. The treaty does not, however, protect you from differences in rates of taxation.
I do hope that you have found my reply of assistance.