When I first bought a Brompton bicycle ten years ago (I did actually have one back in 1990 but the same applies) I did not know how to do anything in terms of repairs or maintenance. During this time I have likened myself to a character from a Jane Austen novel, who if encountering a rear wheel puncture, would probably have got light headed, reached for a laced handkerchief and fainted! I was that person. Thankfully, over the years I have acquired enough knowledge to carry out most of the major repair and maintenance needed to keep my fleet in good condition, that would otherwise require a trip to the local bike shop.
Over the same period of time I have built up a small collection of tools very specific to the Brompton. A couple of new purchases have been wrenches by 'Park Tools' with the addition of a ratchet.
I have one in 15mm and the other in 10mm which is really all you need to replace wheels and performs a few other tweaks.
The addition of the ratchet - which I have to say works really well - makes things easier and a little quicker. I have a few other items by 'Park Tools' and have always found them to be built to last.
Prices vary for these but £9.99 is about right for each. Well worth looking up if you don't have any of these or want to replace what you have.
Stay safe out there people!!