I recently serviced the rear frame hinge, using a standard reamer. I'd been worried about performing this job for a long time, I kept delaying it due to the potential trouble caused by my lack of experience. It all worked out OK and the brompton reamer isn't really necessary, a modicum of caution and diligence will do. The problem for me was getting the hinge bolts out.. in fact I resorted to an unorthodox method of sawing through the spindle instead of drilling out the bolts as drilling was taking forever.