Thanks again chaps.
I received a helpful reply from BaaCommuter.com which I've quoted below in case anyone is interested.
I haven't investigated the
Gatwick Express Card fully yet but the
Gatwick Staff Discount Card looks like it would work out at about £155/month for just Southern Services or £215 if I wanted to include Gatwick Express. I wonder if the 10 minutes saved each way + more trains available would be worth the extra £60. Perhaps I'll have to experiment when the time comes.
Adding the cost of the bus to Victoria it's getting a little expensive. Especially as I'll be living on CTC's £1000/month 'subsistence salary' for the first 6 months. Still... better than renting somewhere near LGW I suppose.
You have a few options for travelling from Victoria to Gatwick.
If you choose to use Gatwick Express you can save 34% on fares by
purchasing a Gatwick Express Partners Card for just £10 a year. You can
then purchase discounted season tickets (weekly, monthly, annual) and
one-off singles/returns. Please visit the Gatwick Express Desks in Gatwick
Station for more information.
Alternatively, you could purchase a Gatwick Staff Discount Traincard. This
costs £27 for three months or £100 a year and allows you to save 34% on
most rail fares in the South East. You could then purchase discounted fares
between Gatwick and Victoria for £144.50 a month (Southern services only)
or £204.80 (all services). You could also use the discount card to purchase
discounted fares to other locations within the network - Brighton,
Guildford, etc (I can send you a leaflet detailing the scheme and the
network if you confirm your postal address). For more information or to
purchase a discount card please visit the Train Desk in South Terminal
Arrivals - you will also need a passport photo.
You could also use National Express Coach services from Victoria. You can
purchase a ticket that allows unlimited use of National Express Coach
services from Victoria to Gatwick (and down to Brighton) for just £25 a
week, £85 a month or £850 a year. The journey takes just over an hour
(compared to 30-35mins by rail) but works out cheaper than the train. The
tickets can be purchased from any National Express desk at Gatwick.
To take advantage of any of the schemes listed above you will need to take
with you either a valid airport ID or other proof of employment.
I hope the information above is of help but please let me know if you need
any further details.