I have a rogue U Value of 0.43 for the external walls on the Part L output document, none of the walls have this U Value and I cannot see where it is calculated from.
Do you have any ideas as to what this could be or could you have look at the model to see if you can see where it is from.
I can see it has flagged a partition rather than an exposed wall - could this be creating the confusion? If so the following may be of interest:
BRUKL Report - Internal Surfaces in U-Value check
Shane Regan | Principle Building Performance Support Engineer
I had some unheated areas next to heated areas which was causing the problem, I have added heating into these areas and this has resolved the problem.