New member but saw your post. Had similar problem on a Landrover 300tdi where wrong pads had been used seems common fault. Trimmed very easily with hand tools to prevent chances of pads meeting and reducing brake performance. Material removed max 7mm at circumference of big disc so perhaps worst case. I assumed that any change in brake efficiency would have be minimal and picked up in MOT test data. Although not as fast as you with trailer full up load 2 and half tons stopped fine, now new and correct pads fitted no perceived difference. Peter