He was quoting me around £3500 for a guaranteed full built type 1 box with the 5 speed set up which uses a 1pc lengthened main shaft (unlike the berg unit which uses a welded lengthened one).
I don't know if it is still true but on the Berg 5-Speed, you have/had the option to get either a welded mainshaft, or a one-piece gear set from Albins/Weddle.