So the quotes are in...

Company S. Panels are 6' 6" x 2' and 3' 3" x 2' (seems imperial is rife in the concrete panel industry) 33.6sqm @ £1580 inc fixings, delivery & VAT = £47/sq m

Company N. Panels are 7' x 2' and 4' x 2', 36.5sqm @ £1999 inc. etc. = £54.80/sq m

But the current 'winner' is

Company H. Panels are 6' 6' x 2' and 4' x 2', 35.2sq m @ 1070 inc. etc. = £30.4/sq m


Waiting on one more quote...

Would prefer the 7' panels as less roof working to do, but almost double the price!