Stuart,
Last time I was in La Rochelle, it was less than €10 landing fee.
Other options Toulouse Blagnac, about €11 and ask it's Airbus's base, you might get to see some interesting aircraft
They also had a pilot shop in the airport, if you find that you need something
Perpignan was also pretty cheap.
I seem to remember some VFR restrictions in Barcellona, which meant going either out to see to avoid the zone, or well inland.
As for Mallorca itself, I've no experience. Sorry.
dp