A quality holder that can be secured to your required place with 2 M6 bolts to give a secure location for the wireless transponder. Will potentially fit other transponders too. This does not affect your statutory rights.
eBay
MyLaps Transponder Holder This is a replacement plastic mount that fits MyLaps #MLP10R120 RC4 and #MLP10R078 Hybrid transponders. New and never used but not in original packaging
eBay
eBay