Hi Sinclas
Yes. The UK/Czech tax treats advises that as a resident of the Czech Repbulic, you would be taxable in the Czech Repbulic on your UK employment, provided you are not in the UK undertaking work for that UK employer.
After your employment with the UK employer commences, you should submit the P85, to let HMRC know that you are not resident but employed by a UK employer (
Get your Income Tax right if you're leaving the UK (P85)).
Thank you