Moogues, are you asking if anyone bought from the Instant Hedge company, or what kind of instant hedge are you asking about?

Not personally, but I imagine they must grow successfully or hedging companies wouldn't sell them.

Thanks Tugbretil. I want to plant an instant hedge of laurels and wondered if there were any recommendations as to how to go about it. I want it to be about 6 foot.

Tugbrethil is in Arizona, USA (and I am apparently invisible!), so do an internet search for UK hedging companies. Most have comprehensive advice pages on their websites, and can also be phoned if necessary. I've personally found them to be very helpful.

I think you mean you want to buy your laurels already grown to 6 feet high? This is tempting but not always a good idea - younger plants establish much more quickly than taller ones. And hedge plants should normally be cut back when planted to make them bush out more at the base so unless the ones you buy are already cut back and bushing out you'll be paying for growth you have to cut off.
You'll be paying a lot of money for the sake of a couple of years growing, and big plants will need more care and watering to establish but if all this is OK with you there shouldn't be any problems.
Take Rosie's advice.
(re laurels, did you know they should be trimmed with secateurs rather than a hedge trimmer to avoid cutting the leaves in half?)

I figured that I could only help in general principles of growing hedges, anyway. :)
When I saw the question, I thought, "Instant hedge? What does he mean by an instant hedge?", so I sicced my search engine on "instant hedge". I got the commercial site, and a number of articles recommending that one not try to get a hedge instantly, so then I asked my question. Learn something new every day!

Indeed we do Tug . Wonder what he'll decide? It will nice if he comes back and tell us.