Mate you need to prise the glass assembly out with a screw driver, make sure you do it from the bottom and make sure you put a rag or something to stop marking the housing. Just take it easy and it should come out OK. If you get a problem just PM me with your phone number.
There is a guide on this forum. There is also a thread on this forum with a link to a step by step guide on the US forum. I don't know what they are titled but an advanced search will find them for you.