A kids' toy - with little bricks and 'mortar', and as I remember it, ground plans and elevations too. Anyone know what it was called? Not Bayko - that was plastic and didn't need mortar.

Perhaps it was Teifoc ?

http://www.clayclay.co.uk/html/toy_clay_brick_kits.html

That does look quite similar - but the bricks look a lot bigger. With the one I remember, you had to be very patient cementing very thin bricks. The Clay Clay made bricks look even bigger still. And they refer to Teifoc as 'from Spain', but the Teifoc site shows them as German. Of course, their earliest bricks might have been different, and the originating date given is extremely vague. At its furthest limit it would just meet the year in which I was given my first bricks and mortar. A little trip down a side lane in a search suggest Lott's Bricks as a possibility. I'll look into that tomorrow. Thanks for your effort.