One hour lessons are a good way to practice skills already taught during your driver training. The way lessons are structured 1 hour is the minimum time you can book to achieve any worth while training. At learn 2 Pass I recommend that you pick the 90-minutes or 2 hour lesson as you will have time to relax, learn and practice new driving skills.
Another use for the 1 hour lesson is, once you have gained experience in driving and have moved on with the basic lessons why not use the 1 hour lesson as a method of transport. (subject to your experience / location and availability of instructor) You can combine driving practice with transport to and from work.
Example:
A Good use for this is if you pay for a taxi to go to and from work, why not pay for a driving lesson instead, so some of the cost of the lesson is covered by what you would have paid out for that taxi.
Cost of lesson £35 minus Cost of taxi you would have paid
As you can see the potential further savings on your lessons.