I don't know how it works in the UK.
But here in Canada, you need to deal with three levels of Government.
You need a licence aka business licence/permit from your municipality to operate from your home, or wherever your business is.
You need to register your company name if different than your name.
You need to register to pay Provincial taxes and collect Provincial sales tax.
You may even need to incorporate. (Provincially or federally).
Federal goods and services tax needs be collected and forwarded on to our federal govt.

The fines for running an illegal business will be more than the cost of doing it right.
Bet your last dollar, that if your competitors find out you're not registered, so will Revenue Canada.

Lastly you need to be registered to get the tax benifits.
Being able to write off equipment, expenses, and part of your home will reduce your taxes a substancial amount, esp if you have to work another job to support yourself short term, and tax credits can be carried forward several years to reduce taxes on future profits.

Even if you start off by direct selling prints...
Say you place some free ads online and in local papers classifieds (you might want to do a little viral marketing by putting "Wanted" ads offering to buy "OC Photobug" signed originals for substancial prices.
Generate some buzz and percieved value.

Then you may want to book a conference hall to host your own private gallery show/sale. Be sure to invite prominant people who can help you out. (art gallery owners/currators, art collectors, magazine editors.
Ask your friends and family to come and buy work to help your show succeed.

Network like hell.

Wow. 3.
these days, that'd be tough.
I charge for event coverage, provide two photographers, and whole day coverage.
To cover three jobs I'd need to hire alot more staff!
but then I could make more money.....
but then there'd be more work.
but I like money.
I hate trying to think, before the coffee maker finishes, first thing in the morning...
I could open a coffee shop.
people like coffee.
I could make money.

there are some tax benifits to running your own business.
everywhere you look there are images.
somebody will buy...but at what price?
George offered solid advice.
The main thing id to startoff right, business wise. Register it. Get a licince.
Where are your intersts and strengths as a photographer? as a busineeman?

Only three pints?
A couple shots would'a complimented that, I think.

I manage to scratch out a living.
I do Weddings. Portraits. Corporate functions. Also a little advertising. Been published a few times.

as for pricing....
Look at the pricing on the pro optics in thier respective companies, and you'll find Pentax is a relative bargian.
Pentax has a habit of offering serious equipment at moderate prices.

You know what'd be cool?
A seperate column, called the "Boxing Ring and Flame Throwing Arena"
That way those who obviously enjoy heated debates, can open a new thread, and carry on, without hijacking, what usually starts off as an interesting topic....

(I know, I know, I'm as guilty as some and more guilty than others...but really, WHERE"S THE FLAMETHROWER BUTTON I asked for?).

not anymore....
here's what he'd look like at my house!
Upset Chicken

warning...clip from a home movie project I'm working on.....
this is the scene just before he gets bbq'd

"Should I buy......."
You might as well be asking junkies if you should try coke.....
HECK YA!!!!

I think slight underexposure combined with slight oversharpening will induce some noise and artifacts.
at any iso.
how are you processing your files?