Hello and welcome to the site. Thank you for requesting I help you with your question. Please clarify for me...where on the tax return do you report this income. Income from property should be reported on supplementary pages SA105 UK Property.
You should also report losses to enable you to carry forward these to be offset against future profits from rental income.
You are correct that when capital is withdrawn at a future date there will be no more tax to pay on it. On future sale your share of the gain from sale of property would be chargeable to capital gain tax after allowance for gains annual exempt amount. I hope this answers your question.