Matthew, do you have Chris Gould's "A Guide to the Austin "65" and Nippy"? If not it would be well worth your while to acquire one (I can put you in touch with Chris).
In it he writes that the 'later' cars (I think this applies to yours) had a standard Ruby instrument panel with exception of the speedo & oil pressure gauge. The explanation of speedos is complex (pm me if you need details) but it boils down to the fact that the Nippy had 1000 cable turns per mile instead of 1040 - this is marked on the gauge front. Chris says Morris 8's used 1000 tpm speedos and they are very similar (and much more plentiful). n.b. Of course if you don't have the Nippy axle ratio you might be better off with one that reads correctly.
Pressure fed Nippies had David Harcourt 60 psi oil pressure gauges, these are not so easy to find and expensive if you find one. Logically I suppose cars with touring engines had the Ruby gauge.
In it he writes that the 'later' cars (I think this applies to yours) had a standard Ruby instrument panel with exception of the speedo & oil pressure gauge. The explanation of speedos is complex (pm me if you need details) but it boils down to the fact that the Nippy had 1000 cable turns per mile instead of 1040 - this is marked on the gauge front. Chris says Morris 8's used 1000 tpm speedos and they are very similar (and much more plentiful). n.b. Of course if you don't have the Nippy axle ratio you might be better off with one that reads correctly.
Pressure fed Nippies had David Harcourt 60 psi oil pressure gauges, these are not so easy to find and expensive if you find one. Logically I suppose cars with touring engines had the Ruby gauge.