:(reversed into my gate and the drivers wing mirror popped out off my octavia manual control ie wire. found new mirror halfords for £7 and it fits but how do I refit it back into the casing thought it would just pop back in how wrong was l. there must be a knack to it.

If I understood correctly, follow the link:

http://www.briskoda.net/forums/octavia-ii/door-mirror-glass-replacement/95911/

Octavia I or II? I have moved your thread to the former's technical forum for the time being.