I've found the WD number lists to not always reflect reality, when I compared the list that included Loyd carrier 'T' number allocation to the actual contract cards that were hand marked up as and when contracts where altered during mid contract execution it was apparent that the lists accurately reflected the original vehicle production number in the supplier contract but not the production reality. For instance, from the Tank museum contract cards it appears that all Loyd contacts were cancelled in November 1944, resulting in entire production runs included in the WD number lists being totally cancelled. This leads to much confusion today as people treat the WD lists as gospel production figures.
Does any archive hold the trailer contract cards?