I was in GameStation.co.uk today and on the shelves by the counter was a few brand new official component cables for the PSPgo. Had 2 stickers on them one sticker had £17:99 crossed out and the other saying now £4:98. This was in the Liverpool,St Johns store. Sorry I could not take a picture as I never had my phone on me today.
On gamestation.co.uk they have PSPgo component cables for £4:98 but it dose not say if there official or 3rd party.
EDIT: For got to mention that also had PSPgo essential packs for £2.50 am not sure what was in these packs.