Key (replacement items)
From WikiLEC
Following the 'current trend' of many cars using 'Flip keys' for the ignition, I have discovered that the 'blanks' for our cars are given the code number of YM28 (It's a GM pattern, but also listed for Lotus - and as the ignition barrel is a Vauxhall/Opel Astra part, it's hard to think that it's wrong!)
Have a look at http://www.rclick.co.uk/product_info.php?products_id=412 You'll need to click the GM logo, and then there are other options - the YM28 on the right is the one you need (well, it says it's for a Lotus, and looked right to me!)
The 'blanks' are £2 each, and they can also supply a selection of fobs to suit your alarm system - or just a blank one if you prefer.