Holdens supply 52mm (£76+) and 60 mm (£86+) clocks which they say are made from genuine Smiths designs and tooling. What you need to be careful of is the shape of the chrome bezel to match your existing ones.
Hi Doug
I did look around and whilst you can get Smiths 60 mm and possibly also get the rounded bezel, the Morgan clock with inner and outer marking seems specific to Morgan and has to be ordered as a bespoke part. If you look at it on that basis as a bespoke part then £152.00 delivered isn't that bad.