Octofish or Jellypus?

I was wondering if anyone can help solve a family argument? I have just spent a lovely week on the Pembroke coast and whilst ambling along Amroth beach we came across this fine specimen.

The tide was on the way in and we’d come across a few jelly fish so my thoughts are that it is some sort of variant. However I have never seen a jelly fish with suckers and not one with such thick tentacles.

My partner on the other hand is convinced that it’s a type of octopus, due to the 8 tentacles. I think that the colouring is wrong though. Although I confess that I have only ever seen them in pictures and cartoons.

Does anyone have any ideas?