In the past, the LDMCC have not accepted a waiver of liability. The British insurance companies deem that any aggressive American lawyer can get (and apparently have) around any such document written.
Further, if the sale is via a third party as proxy, deem this to in effect as selling directly to the end party. How this can be distinguished from purchase by an intermediary that decided to re-sell the item I do not know. However the insurance companies tend to be a cautious lot, and have shut down most of the smaller marque's spare sales to places like North America. Well not entirely. Clubs can get insurance to sell to North America, but the premium is so high it averages two to three times the additional typical annual sales generated.
Technically the intermediary would take on the liability of the sale, but they could always argue that they did not have the item manufactured, and so pass the liability back up the supply chain. I looked into setting up a limited company here in the States to buy and resell LDMCC spares to the North American club members. The issue of whether this would be an acceptable liability firewall for the insurance company had yet to be looked into, but the annual licensing fee to keep such a company (I looked at Pennsylvania and Delaware) was about $400. That was about what the LDMCC was shipping to North America in a good year, before the insurance crisis. So it did not look like it would be self-sustaining, but would require a generous donor to keep it subsidized. I decided that I did not meet the qualifications!
-Doug