Took delivery of these yesterday, will post some pics later.
I've liased with a couple of suppliers in Japan and S'pore to supply these and opted for www.partsdivision.com in S'pore. They were prepared to do a lot of investigations and checks into confirming that the parts would work/fit the UK spec car. If anyone wants to approach them for these or anything else, I can give you the contact details.
The total cost for these including shipping and insurance was $765 SD, ~£250+money transfer fees. The cost of the acutal parts is $620 SD.
I think the Japanese supplier www.japanparts.com can supply them cheaper, but I was not that satisfied with the amount of information they were prepared to provide. The manual is in Japanese and partsdivision were prepared to anotate it with some key information on connecting up etc. The Lexus guys should be familiar with the removal and install process of the interior panels as the pictures look silimar to other english manuals I've seem.
Anyway, the items are original Toyota parts, good build and paint quality and include the wiring harness and connectors, screws etc.
I'm going to see James at Lexus Woodford tomorrow to see when they can fit, and will update after that.