Law / Looking for info regarding registering a business in UK but operating in Poland [10]

I was wondering if anybody had some information for me regarding operating a business in Poland.

I am a British citizen and I am looking to register as self employed here in the UK but I will be living and operating the business in Poland, is this possible?

Does anyone know to which country I would need to pay taxes to and would I still have to do my self assesement forms for the UK every year?

My sales would be in pounds sterling but my expenses would be in Polish zloty, therefore is it possible to get a foreign currency account.

I would appreciate as much help/info as possible.

Many thanks in advance.