Not entirely a success, but worth posting since I tried combining a number of techniques (and tutorials) with this. Firstly the alley was just a JPG I got off the web, then took it into Photoshop and used the vanishing point tool (a VPE file, I think) to make it into a 3-D object or box. Then took the VPE into After Effects, following a Video Co-Pilot tutorial and animated a camera move from high angle in the background (hence the radically distorted perspective, which I like!) to low angle foreground. I then tried to composite a 3-D object (the mini car) into the scene, animated the car in Lightwave, with a similar camera move (starts high, comes forward and dollies down) and with less success, masked in a shadow for the car. The lighting was never really going to match and keying out the background to the car only taught me to use an RGB sequence as a render from Lightwave. I'll get round to that.
Finally I tried some Trapcode Particular rain effects over the whole thing - inadvertently reversing the rain at the start of the scene, in the background. I don't know how I did that. A negative loading for one of the emitter settings? But anyway I kind of like it. I got the rain idea from a tutorial by Ik0, a French motionographer based in Nantes, who has a cool blog (and tutorials).
I will probably re-do this one and try and get the rain splashing off the roof of the car - the neatest part about Ik0's tutorial - but for now, this is the state of play.