I recently had my sons photos done by Memory Gate Photography and thoroughly recommend them.
It was a deal through savvymummy.com (they've advertised on here, its groupon for sw london mums) and its was £37.50 for the shoot plus 2 photos, 1 8x10 and the other A4 and a DVD slideshow to show family members, the idea being they then buy the ones they like which is fair enough.
Two photographers came to the house with all the kit, they were professional and lovely and prints were delivered by hand a week later. Brilliant.
I am getting them back to do his photos at 3 and 6 months and the shoot is free you just pay for the photos from £20 each, canvases etc obviously more but they do have to make some money! Great service and photos.