The solution was to use plastic connector blocks. Screw 2 stacked
blocks to the rail lengthways, then 2 stacked blocks to the support beam
similarly.. Then bolt both sets of blocks together, side by side.
Unfortunately the socketed connector blocks are not available with the
right orientation, so we had to use the B & Q version which do not come
with sockets or bolts which was a bit of a pain.

On Thursday, 3 November 2016 12:37:52 UTC, Capitol wrote:

The solution was to use plastic connector blocks. Screw 2 stacked
blocks to the rail lengthways, then 2 stacked blocks to the support beam
similarly.. Then bolt both sets of blocks together, side by side.
Unfortunately the socketed connector blocks are not available with the
right orientation, so we had to use the B & Q version which do not come
with sockets or bolts which was a bit of a pain.

Who knows what that means. But it doesn't sound good.