Well David @dirtylittlefokker, I broke the ground with a handsaw. The base is now 1190 x 160 mm.
I phoned the hardware to check for 4 and 6 mm dowel. The salesman looked for what was available. He said "We got both sizes." Then questioned my choice for the smaller by saying "That 4 mm looks small". I said "Yes, it's under a quarter inch". "That's the one alright", he said.
Meet the 'Minder', his name is Terry Ican. Just because he 'minds' everything, he often thinks he can tell me where everything ought to go, like he is doing now. His internal mantra is Ican, so sometimes he's a bossy little s&*!. Unfortunately he likes to get in the way of things. He will appear when least expected.