I had the same situation and a similar quote from a local auto-locksmith.
The explaination for the price was the programming of the new keys chip to match that of the old (to disable the immobiliser). This allows the key to start the engine, otherwise that will just be good for opening the door (so consider if Timpsons will include the programming).
Also consider looking into how much it is to get a remote feature added to the key and car - as the 3 of 4 locks of mine have needed work to get them working again (first drivers door, then boot, then ignition) as I think the parts inside wear out.
