Hi Lucy,
Living in the Glasgow area can understand your flight difficulty, but really that is going to be a given for you.
Went into vacationstogo.com and have seen two Celebrity cruises that I would go on if it was me. The Med is very nice at that time of year. Prices quoted are for inside cabins, but both outside and balcony available at significantly higher cost.
1) Galaxy for 11 nights, leaving on Sep 22 from Rome $1399 plus 6-7% tax, about £750 cruise only. You can fly return for less than £100 from Glasgow Prestwick to Rome, and the flight is around tea-time so you can drive without getting up at crack of dawn. Best to get there a day or two before, and see Rome (also if flight delayed you wont miss ship). If you go for this come back to me and I will tell you how simple it is to get to Civitavecchia from Rome....we did this last June.
2) Century for 10 nights, leaving on Sep 19 from Barcelona $1249 plus 6-7% tax, about £675 cruise only. Cheapest way to fly is from Newcastle with Easyjet at less than £100, long drive though. Flyglobespan should not withdraw Barcelona, it is extremely popular, so shorter drive to Edinburgh but flight is breakfast time!! The port is less than 10 miles from airport so easy taxi ride, and scope if flight delayed. An extra day in Barcelona pre-flight is personally recommended.
We were on Century June this year, and my sister has been on Galaxy which is to be refurbished sometime before 2008 summer season. She thought it was superb last year. In terms of dress on a 10/11 night cruise there will be 2 or possibly 3 formal nights, the other nights very smart informal. They promote themselves as a 5 star line, and there is no doubt it is at least a 4.5 star for me.
A 3rd option I noticed is the Emerald Princess 12 nights Sep 21 going Barcelona to Venice at $1843 + tax. Downside is different airport in and out and with having to take a car your source airport would need to be the same as the one you fly back into which is not easy as no Scottish airports have direct Venice flights.
Anything else just come back or pprivate message.