Transfer-back of parents' bank deposits will not induce any income tax implications for parents

Hi Sir/Madam, My parents do not have any UK bank account until they arrive and live in UK. They are retired people with no employment income at all. In order to sustain their living expenses in UK, before the day of their arrival at UK, they transferred their bank deposits from their overseas banks to my overseas and/or UK bank account as a kind of their deposit in my accounts. And then, after they open their sole UK bank account, I transfer back their deposits to their respective UK bank account. In this sense, I think my transfer-back of their deposits to their bank accounts are NOT treated as any gifts to my parents and so no gift allowance implication is applied. Please correct my thought if not the case. I have another concern. May I know if my transfer-back of these deposits to their bank accounts will not take any income tax implication for my parents because these deposits are originally owned by themselves (under their name of bank account when they live in their home country). Also, they are not required to submit their self-assessment tax return unless their other foreign incomes are more than GBP 2,000 of dividend allowance. Thirdly, for myself, I will declare all foreign income and UK income (including those saving interests arisen from their deposits) for my residence period in UK, and also report this in my self-assessment tax return. I have applied for split-year treatment for the tax year. For my above queries, please correct me if my thought with further plan is inappropriate. Thank you.

Hi KuenHK,
Yes you are correct.
The transfer back is not a gift as it is their money.
No tax is due on the transfer of the capital but they may be liable to tax on any interest or dividends that is then generated.
If you qualify for split year then you only report any foreign income for the UK part of the year:
Residence, Domicile and Remittance Basis Manual
If you do not qualify then you will need to report all your foreign income to the UK:
Tax on foreign income.  
The guidance at RDRM12150 at www.gov.uk will help you work out if split year treatment applies. 
Thank you.