Hi Simes,
there are a couple available on Amazon.co.uk, and more available on ebay.com, although the latter seem to be mostly from sellers in the US. The cheapest option currently seems to be the 'totally flying' combination pack for around £5. Unfortunately the original game seems to be retailing at between £20 and £34 in the UK if Amazon is anything to go by... which is pretty amazing for a 12 year old game.. !!
If all else fails, PM me as I have three commercial copies of the game here in North Wales and would happily sell you one.
cheers,
Pobs