Thanks to all for your input - I will have a look at the 'via Southampton' and SVR options.
I am afraid that the final suggestion from TG cannot be considered because I hate long distance coach travel and would not use such services unless there was absolutely no alternative.
Good luck!
Just a quick one on this Bob, I thought of you this morning when I got to Reading (en route to Bristol
TM‡) and the Gatwick service was suspended due to a broken down train - the fallback being suggested was travelling to Paddington, across to Victoria and out again to Gatwick - perhaps worth bearing in mind for your trip - if the Reading-Gatwick service falls over, there are very few other options other than that being suggested this morning which adds a large amount of time to your trip.