hole cut in base of bin where gap in lip is for air flow into tandoor to assist charcoal burn

topped up with perlite and then finished of with a foamed perlite / heat resistant cement mix to keep insulation in.  Will top this later with a waterproof cement sbr latex slurry - just in case it ever got left out in rain.  Will also cut some slots into clay pot top for the skewers to rest in to retain heat.

How did you get on when you fired this beauty up ghoulie - looked to be a very interesting project !

Went ok - but I only gave myself 5 out of 10 for the results.  My fault entirely - loaded too much into it at once with differing cooking times needed.  4x large chicken pieces and 4x lamb chops.  One burnt, one not quite done.  Didn't seal the insides with salt water - so naan stuck firm.  All sorted now - you have to learn by your experience the hard way !