Updates depend on your device's CSC code, (Country Specific Code).
To locate this, go to...
Settings > About phone > Software information > Service provider software version (see screenshot)
What update are you currently on?
Your screenshot shows a mismatch of CSC codes which would seem to prevent you receiving updates.
OXM = Non regional CSC code... to be expected
BTU = Samsung non carrier branded CSC code for U.K.
EUX = European, non country specific code
O2U = U.K. carrier code for carrier branded network O2 devices.
Put simply, your phone does not know which firmware you should be receiving.
Try the following...
If this does not work you may need to contact a Samsung Service Centre.