Hi,
If you are resident in Switzerland in the tax year in which you withdraw funds from your tax return, you will be subject to Swiss taxes and not UK taxes.
If you are resident in the UK at the time, you will be liable to UK tax and not Swiss taxes.
You would have to request a certificate of residence using link below, to give to the Swiss tax authorities, along with any other forms they would require, to claim back any tax they may have deducted.
How to apply for a certificate of residence to claim tax relief abroad
Have a look at article 18 of the UK / Swiss tax treaty for more information.
1977 Switzerland/UK Double Taxation Convention as amended by the 2009 Protocol
Thank you.