Quick question, what car does the 52mm throttle body come off? I work next to a scrappers I'll see if they have anything in.
Could be fitted to a lot of marques fitted with the 1.8 K series engine as per PQD44's previous post.
I got mine from the scrappies, it came off a Land Rover Freelander, I only wanted the alloy manifold but had to buy the complete manifold for £35, when I got it home and cleaned it up it had the 52mm throttle body and the blue fuel injectors 'spot-on'
There are some identification marks on the top of the throttle body flange "TV1" is the 48mm and TV5 is the 52mm.
If you take a wire brush or some wire wool and clean the area on the flange the marks should be easy to see.
The identification marks are on the image below.
Brian.