Applied online via their website. After around two weeks they emailed me and arranged a phone interview which comprised of questions such as why did you choose Imagination, what have you studied at university, a little bit about MIPS architecture and questions regarding pipelining, interrupts and a linked-lists in C. A few days after they arranged a Face-to-Face interview with me at their HQ. This comprised of more difficult questions, particularly those at the low-level, things like designing counters in logic, creating a NAND only XOR etc. Just make sure you can do a little Boolean algebra. They're not looking for people who can answer every question perfectly, they're looking for those who think about it and make an attempt regardless rather than those who just say "I can't do it" or "I don't know how".