After extensive trials during 1925 - 1927 , Collett was satisfied with the performance of his prototype , subject to minor amendments .
After extensive trials during 1925 - 1927 , Collett placed an order for eighty more with Swindon works ( Lot 254 ) in 1928 .
After extensive trials during 1925 - 1927 , Collett was satisfied with the performance of his prototype , subject to minor amendments and placed an order for eighty more with Swindon works ( Lot 254 ) in 1928 .