We pay our staff £7.30 p/h, so £9.56 is not a great deal of difference, especially when you take into account all the other costs involved with having your own employees. Not to mention the stress of making sure they always have enough work.
As a ball-park-figure, we tender for contracts based on an estimate of the cleaner hours required x £15 p/h. So if a large one-off contract comes along and we need temporary staff to cover it, I would definately be interested in using an agency.
I have not done it yet, so I am pleased to now have a bit more info, and I am glad MK1 had a good experience