Eisco Retort Clamp 3 Prong Rubber Jaws

We recently bought a Thule cycle rack to carry 2 cycles fitted to a towbar. It came with 2 different length 2-headed clamps for securing each cycle to the rack frame. These don't bear any weight of the cycles but prevent too much horizontal movement. The one for the inner bike was too short for our cycles, almost non adjustable and therefore useless. I then scoured the internet for a 2-headed clamp of a suitable length, but with no results. Remembering my days in the chemistry labs, I bought 2 Eisco Retort Clamp, 3 Prong Rubber Jaws, Order Code: 52-3367 and one RVFM Bosshead clamp, Alloy, plastic coated, Code: 52-2125 and made a double headed clamp arrangement, adjustable in all directions and perfect for securing the inner bike to the rack. Cost with delivery ~ £9.