"Could I interrupt here, because there is an alternative explanation, which you are particularly well placed to examine. You know the argument that it is the alchemists in the laboratories who invent the sweet new kits"

In this quote, E. P. Thompson is recommending that there is an alternative description to the present argument. He is suggesting that it is not the alchemists in the laboratories who invent the sweet brand-new kits, however rather that there is an alternative explanation that requires to be taken a look at. He thinks that the person he is speaking with is particularly well placed to analyze this alternative explanation, as they have the knowledge and experience to do so. This quote is a call to action, motivating the individual to take the effort and check out the alternative description. It is a suggestion that there is constantly more than one way to take a look at a situation, which it is important to consider all possibilities prior to making a decision.