I found this really handy piece of code in this forum earlier today, and it
fixed my problem, the PivotTable was retaining old data in its drop down
lists.
I added this code and all was fine.

With ActiveSheet.PivotTables("WL")
.PivotCache.MissingItemsLimit = xlMissingItemsNone

That is until I gave it to someone else to use and now it causes an error, I
have on error goto reset defaults, which it does.
I've checked the other machine for updates and it is up to date, I've
checked the references and they match.
But now I am unsure where else to look.
How do I check why the line causes the error?