You should be able to get the ALK for around £110-£115 inc VAT/delivery. You'll pay an hour or so install at a garage, so add £25-£50 on top, unless you can get access to some car ramps and have a bash yourself.
£140 is expensive, but they're giving you fitment - it's not entirely FREE, nothing is so you're just paying for it as they can't compete with mail order companies.