Results from bolt testing were as I thought - they all failed! We chucked the M6 bar, and ground away the last inch of thread from an M10, which thankfully works. Bolts were re-tested to 6kN, and were still holding strong. This is nearly twice the load we need them to carry. Disaster averted.

So on Friday morning we took delivery of a load of 47x200 TR26 timber lengths, and also some smaller 47x100 C16 lengths which we'll use for temporary diagonal bracing and then later for ceiling joists in the bathroom. Here's the first corner:

Which then quickly progressed to this:Pinky and perky:

And at the end of the second day, where we ran out of timber! Emma is just finishing off nailing the diagonal brace to a steel angle bracket which we fixed to the concrete.Another view just before we attached the out-of-plane diagonal:

Have just ordered another 30 lengths of timber, which should keep us going for another few days! At the rate we're going we should have the whole frame up in no time at all.