In reply to Sonya Mc:
If you are a complete beginner, I'd suggest ideally 2 or 3 x 2 hours lessons on an indoor slope to start with to get to the grips with the basics, then morning ski school for the first week's resort skiing, with time in the afternoon to practice on your own.
IMO it's a false economy skimping on ski lessons, particularly when you're first learning, as you'll just ingrain bad habits and it will slow your technical progress.
And I'm with moffatross that you're unlikely to be able to really get down anything with real control or confidence after just 2 hours, and struggling to do so without any further tuition could just knock your confidence, as well as risk injury.
Also, I don't know what the Lecht is like, but at the other Scottish resorts I've been to the blue runs can be pretty gnarly compared with their equivalent in the Alps as they tend not to be so heavily groomed (if at all), not to mention the rocks, heather, holes, lack of piste markers etc.
Once you've progressed to early intermediate stage (after a week or two's skiing) you can get quite a lot out of a couple of hours 1-2-1 private lesson in a week's skiing holiday.
There seem to be plenty of British skiers though who seem to think that ski lessons are unnecessary. You can spot them a mile off from the chairlift.