As I posted recently I am not going to be buying the Brompton Toolkit - mainly as I just think it is rather pricey.
I got my little midget spanner in the post today and as promised here is a picture of it next to a Bic pen to give an indication of its size.
To my surprise also enclosed for free was a 10mm and 12mm version which was a bonus. The 15mm spanner weights probably less than 50 grams and easily copes with taking taking a wheel off. I had a go with it and encountered no problems.
I am very pleased with it and for £4.69 I am much happier. Being so small and light it will go with me on all journeys.