Thanks very much for the offer of assistance, it is much appreciated.
I managed to access the various items after unlocking the base plan.
The items had nothing to do with the base plan and most of them were in level 1.
I don't know why the 'lock' happened and was not aware that a lock on the base plan would make furniture items unaccessible.
If it will help I will happily send you the file but I assume whatever happened has now been reversed - sorry

Once again many thanks for the offer

Richard