the existence of a mobility clause in an employment contract does not prevent a dismissal being by reason of redundancy (under ERA 1996 s.139(1)(b)(ii)).
The correct test to apply is the "factual" test (ie whether work has ceased or diminished in the place where the employee was actually employed) not a "contractual" test (ie whether work has ceased or diminished in the place or places at which the employee agreed to work under his contract).
For notes on the legal background see Mobility clauses .