After eating this at a tapas place last Friday, I decided to recreate it and found that Delia had it in her How to Cheat.
Instead of the McCaim's crispy potato bites, I made my own by parboling potato cubes then tossing them in olive oil and blacl pepper and baking it in the oven for 25-30 mins.
The dip was superb and will definitely be making this again!