Judith,
             I booked direct with Thomson on the web. If you really want to go to Arillas I'd ring them direct (0870 550 2590) explain how much getting to Arillas meant to you, so much that you would fly from Glasgow, is there any way this could be done etc etc.  You will probably find them more helpful than Lunn Poly. If your holiday to Ibiza is with Thomson I'd give it a go as Arillas, for me anyway knocks spots off Ibiza, or indeed anywhere in Spain. Good luck if you go for it and don't be backward about asking- they want to keep you a happy customer
                                          Ivan