Easy - Independence of the Seas out of Southampton for a short taster cruise on 29 Aug 09. Best ship for entertainment, facilities and for accessible cabins.!
I think if your planning a cruise for the first time, you will be more than impressed with most of the established cruise companies. We are going with P&O in October from Southampton. They oddered free parking as part of the deal & I'm sure you will pick up a good price with cruise.co.uk.
P&O are very good at looking after the disabled passengers.
I you are wanting to see fantastic scenery, try the P&O Oriana cruise departing Southampton, 23 August 2009, to the fjords, returning 30 August (seven night cruise).