Work has been a bit slow this morning, I noticed an error in the plans, it is not insurmountable but it is annoying, I am just glad I did not pay for them.
The error appears to be in the support for the main frame, the plan says that when attaching the rails to the frame just to use a few screws, as the weight is held by the head and footboard legs. This is true of the footboard, but going by the plans not the headboard, as I will show in a minute.
Anyway, having worked on a workaround, I continued with the headboard, which, other than the top board, which will go on at the last minute to avoid damage, is now finished.
As you can see there is space for the side boards to fit into the legs, but there is no support for the mattress frame, so I have two options, either to attached a third piece on the lower part of each leg to support the frame, or drill and put a bolt through the leg, rail, and frame on either side.
Anyway, I have time to decide on that, tomorrow I start on the footboard.