Rear wiper has not worked since I bought the van and I finally managed to source a replacement on Ebay for £50. Seems like it came off a Toyota Previa but it is the exact same part. Bit of a job to get it the wiper to park in the right place, and I broke the bolt on the outside that pulls the wiper arm onto a spindle (don't overtighten!) but luckily it was the old one I broke and the new one was quickly fitted. So happy to get this working finally.