As an example AKS Tuning state a price of £420.00 for this.
https://www.akstuning.co.uk/shop/content/10-servicing
*no affiliation/other specialists are available*
Andy.
That's without the VVT unit though. not that the VVT is always needed, just some people who have the chain noise have often needed the job doing again because the VVT was faulty too and there is still noise.
On mine, i went ahead and changed the VVT unit "while i was there" and felt heart broken giving over £400+ for the VVT.
If you're fairly handy with tools give it a go yourself, Rich83 done a full guide on it. I got my locking tools from ebay for under £30 and they work a treat... I've done around 5 cam chain & tensioner replacements with them.. good as gold! just make sure you buy THE GENUINE socket for the VVT bolt. Don't skimp for the laser rubbish! it will shatter on you!
I also don't have anything bad to say about the full eBay chain & tensioner kits (from the right seller). 2 of my mates opted for the cheaper kits, cars still going strong years later!