Since adding the oil gauge I noticed no speedo reading.
I initialy suspected that the connector had just popped off the speedo itself.
Anyway, I wish that was all it was!
The connector had snapped in 2 meaning the inner cable wasn't secure.
What a fiddly job...
Managed to glue the 2 parts back together which meant holding it in place in the most awkward position known to man :-)
No doubt there's a trick to this (probably lowering the steering column and removing the wheel).
Hopefully that should hold it.