If you can get a USA company to do store-and-dispatch for you, why can't the Chinese sellers do that in the UK?
Aside: I was looking at something, cables for a multimeter IIRC - cheaper shipped from China than the delivery cost from UK providers; I can't get my brain around that. It means Chinese shippers are getting cheaper shipping for the Euro stretch than local shippers? (Local providers aren't overcharging the shipping AFAICT).
Chinese shippers in many cases do get cheaper rates than local shippers. The Universal Postal Union sets rates between postal services for different countries, which are called terminal dues. I'm not sure what the terminal dues are for China -> UK specifically, but for China -> US, the shipping is much cheaper for posts originating from China to the US than from within the US to within the US. It's centered around China -> US terminal dues, but this article[1] gives a good overview.
This is also why you won't see many Chinese sellers shift wholesale inventory overseas. It might lessen the transit time from purchase to delivery, but would drastically increase their shipping costs.
Related to the aside: It has been this way for a while. Check out ebay listings for < $1 USD shipped. Pretty much anything you could buy in a dollar store and more can be shipped to your door for less than a dollar if you are willing to wait up to 30 days sometimes. That entire inter-country shipping system is broken. From what I understand, they hand off the package with no fees going to the USPS. I believe it is that way for most tiny packages.
It's not that no fees go to the USPS, but the fees that go to the USPS are pre-negotiated by the Universal Postal Union (UPU), which is a multi-national organization within the UN that the USPS is a member of.
China is considered a Group III country by the UPU, which is a "mid level developing country". Other countries in that group include Brazil, Mexico, and Thailand. The US is a Group I "Industrialized" country. Shipments from a Group III to a Group I country equate to about $1 - $1.50 USD per pound (it's not a linear scale and per/lb rate fluctuates based on total weight).
Aside: I was looking at something, cables for a multimeter IIRC - cheaper shipped from China than the delivery cost from UK providers; I can't get my brain around that. It means Chinese shippers are getting cheaper shipping for the Euro stretch than local shippers? (Local providers aren't overcharging the shipping AFAICT).