These vehicles do sometimes put out random U codes (codes generated because of communication issues) which aren't 'important' and can be ignored. Would be nice to know the code it had. It could of course be the instrument cluster or wiring to/from it.

Where I work we have used BBA reman for repairs to modules. http://www.bba-reman.com/uk/ They do have a very helpful trade forum on there, I'm sure I've seen some posts about clusters on there.

Can't honestly remember what I used once to bypass the connectors, probably the 'heat shrink' type of bullet connectors rather than soldering for the reasons you posted.

Have had a similar fault but very intermittent recently with a Focus, once in about 3 days it won't start, no crank, but if you turn the key off, and on again it starts so not able to see it in a faulted state.