I interviewed at Oxford Instruments (High Wycombe, England)
Interview
Thorough technical interview. Expect in-depth "debate mode" interview where they really will test your depth of understanding of the subject. Even if you don't make it (I didn't), you'll have a sense of satisfaction of having involved in a really fruitful engineering discussion.
Interview questions [1]
Question 1
Gave an example of a simplified version of one of their equipments. The discussion was around 5 ways I had to come up with which could be employed to meet some clearly defined optimization/improvement targets.