Offshore savings

Good afternoon, I'm from Jersey, but moved to the UK four months ago for work. Am full time, PAYE. I still have my Jersey based offshore account, which will have generated a few thousand pounds in interest since I've been UK based by the end of the financial year. I've never done self assessment before, but will I have to now as a result of this being non-UK derived income? My assumption is yes. Also, as I'm a higher rate tax payer, would I still get £500 worth of allowance? Thanks

Hi,
You will need to review the statutory residence guidance at RDR3  and take the statutory residence tests, to determine your tax residency.  
You may also need to review the guidance for split year treatment.
If you are UK resisdent for tax purposes for the whole tax year, you should look at split year treatment to find out what you should declare.  
If you are not tax resident for the whole tax year, you only declare your UK and world-wide income from the date your arrived in the UK.  
A tax return is required to claim split year treatment, world-wide income and non residency.
Thank you.