I have a reference for TRW brakes saved in my service notes for a “fitting kit” part number TRW SFK111 at £9.39. Don’t know supplier but hopefully you can track down on the net. Think that will include the clip that you are after.

Doug
2011 Plus 4 in Rich Maroon

1972 750 “ComDom” sprinter
1958 Triton 650
1992 Triumph Trophy 900