Possible insulinoma?

Hi all

Been having symptoms since 2018.. started with constant low blood sugar to this day, always have a pack of sweets on me or glucose drink.. 2021 MRCP found a 12mm mass on tail of pancreas which they said was a splenunculus?could this be mistaken for a insulinoma? Always have a degree of dizziness.. and brain fog.

Any tests I can arrange that would indicate this? I live in the UK.