Stewart,
From Greecelover's initial (and only) post on Feb 2nd I conclude they booked a flight-only deal. If that is the case I do not see how the airline can change the departure point without offering either:
the option to cancel with full refund
or
the option to continue with agreed compensation
or
the carrier arranges transport from initial to new departure airport at their cost.
Consider the position were the passengers booked from, say, Aberdeen to Fuerteventura to be told 6 weeks prior to departure that flights were now from Exeter.
If you are correct in so far as a "package" has been booked and the flights, being a part of that package are provided by Air Malta then Greecelover should be complaining to the tour operator as the package is not as booked. Departing from East Midlands instead of Birmingham is as inconvenient as, say, having the resort changed from Fuerteventura to Lanzarote. Not a big distance but significant.
With respect to flight only deals - these are best covered by the EC261/2004 articles. Article 8 covers Right to reimbursement or re-routing. Point 3 refers to the operating cir-carrier's responsibility to bear the cost of getting the passenger from an alternative airport to that for which the booking was made. No reference is made to "resort" airport and hence, as these articles apply to all EEC countries I would argue that flights in either direction are equally subject to these rules. Returing the passengers to East Midlands is NOT Birmingham (originally booked) therefore cost of transfer to be borne by operating air carrier.
IF Greecelover booked a full Package then this is best covered by
The Package Travel, Package Holidays and Package Tours Regulations 1992. Point 12 is titled
Significant alterations to essential terms and requires the tour operator to inform the passenger and permits the passenger to arrange (with the Tour Op.) a suitable alternative package (from Birmingham presumably) or to seek a full refund. Compensation may also apply depending upon the T.Op's. T&C's and the length of time before dep. the notification is provided.
No matter which condition applies I believe these passengers have been treated in a cavalier manner.