options
ben, i don't wish to sound negative but as a location photographer (& a yak 50 owner) working in central london for 15 years, much of that traveling worldwide for plc's can i say that you are considering entering a business that is:
a) cut throat
b) full of competitors who have assisted since the age of 18-20
c) awash with portfolios built up over many years
d) cutting its day rates every year whilst time hungry raw processing has replaced dropping the film with a lab in EC2
e) and without sounding tired of it (i'm not...its a great job) a dying trade as we'll all be taking high res stills from hdv cameras before you know it.
so.. would i recommend it ? yes... 20 years ago but at 30-33 starting from scratch... no way & i would hope that you'd do a bit more research - the last place a designer/ad agency will look is the yellow pages & people that do will ask you to photograph their cat or old granny.
starting out when i did was fine and the lifestyle has been unbelievable but you really need to look elsewhere in my opinion.
hope it works out but i'd do something like the flying micro-light school and have some fun outdoors