right, the listed box for the valver is the SP-08 box (same as the 172), and the one listed for the Williams is the SP-07 box
both boxes are identical in size, the only difference is the SP-08 is 70mm @ engine side, and the SP-07 box is 85mm engine side
ive ordered the SP-07 since the adapters im getting are 80mm, and ive ordered an 83mm silicone bend so it should clamp down on both sides easy enough
the SP-07 is £169 from Motor Sport World delivered