A factor of 5 seems too much. If a kg at retail is £50k, let's say £60k when cut to 80%, this would mean the dealer buying it at approx £12k per kg and that mid

A factor of 5 seems too much. If a kg at retail is £50k, let's say £60k when cut to 80%, this would mean the dealer buying it at approx £12k per kg and that middle layer would be buying it at £2k per kg. The price rises at each level but not by the factor you suggest, it's more likely to be by a factor less than 1 for each level.