I agree with CM that it is no big deal. The change was published both in an ATSIN and in the most recent AIP amendment.
Where I work we will pass QHN to everyone, with QFE available on request and also airfield elevation available on request. Previously we had a mixture of QHN and QFE in the circuit depending upon who was flying the aircraft.
When the ATSIN first came out I checked with the CFI at the flying school and the instructors had already discussed the change and were all in favour of using QNH only.
Give it a few weeks and no one will bat an eyelid.
DBB, When did they last use QFE at the big airfield with the shiny new control tower where you work?