I think it this stage we are more likely to see the cold pool over the UK rather than south of it. The GFS 6z and most recent GEM, ICON and UKMO all back this up. Previous GFS and most recent ECM had the cold pool sinking south and a less cold (but still cold) NE to Northerly set in after a shorter-lived blast from the east.
The 12z's from the GFS, UKMO and ECM will be crucial this afternoon/evening I feel.