massuch:
http://www.crystal-smile.co.uk/teeth-whitening-process.asp
I'm gonna be doing the above. It can be found in Brent Cross Shopping Centre, London or Silverburn Shopping Centre, Glasgow.
£99 for 1 hour and they apply the stuff to your teeth about 3 times during the hour and use the blue LED light stuff. They claim to use non-peroxide solutions which are less harsh on your teeth but still give the same effect of peroxide based stuff.
I wouldn't bother. I tried something similar which was offered at Bluewater for around the same price. Did not notice a difference at all. The % of hydrogen peroxide is less than that contained in the Crest Whitestrips Supreme. It's the hydrogen peroxide that actually bleaches the teeth. It is like paying for someone to use the equivalent of a weaker home whitening kit 3 times in a row.
I've also been to the Smile Studio in London and bought one of their take home kits. That worked pretty well as it had a decent % of hydrogen peroxide (about 12% I think). I noticed a difference after a few days of use and so did other people. Crest Whitestrips work just as well, if you get the supreme strength, and they are cheaper.
I buy mine here directly from Crest in the UK: http://crestwhitestrips.co.uk/products/Crest-Whitestrips-Supreme-Dental-Strength-for-Dark%2C-Brown-or-Yellow-Teeth.html
Try not to drink tea, coffee, red wine, coke and other staining foods and drink during the whitening process as this will slow progress. I also find myself 'topping up' every 3-6 months or so, as consuming those drinks will gradually knock your teeth back down a few shades. Tea stains white cups/mugs - it does the same to your teeth!