Tax Advice HELP!!!

Hi Everyone

I need some advice, and this website seems to be a good place to ask.

Here is my situation:-

I am currently employed Mon-Fri 37.5 hours per week as a video editor for a large corporate company and therefore pay tax and NI via PAYE.

But in the evenings and at weekends I live a different life as a editor/cameraman, All my earnings are paid to me either as business cheques or as direct to account payments, after invoices have been sent.

My worry is that I have been so busy that I have let my tax planning slip.

I started work as a freelancer in March 08 - But have not informed the Inland Revenue YET! As I worried there may be a better way or I may be fined for doing it late.

I just assumed that I could fill out the self assessment form at the end of January 09 and all would be fine. But not having seen the form, am I being naive?

My freelance work although it pays quite well, I have invested an amount equal or more to any gross income (obviously minus my full time salary) into equipment in the belief that it was deductable against tax is this correct and if so at what rate? And do I need to do anything in addition to the self assessment to get this benefit.

In my full time salary I pay the 40% tax rate, is this rate applicable to my freelance income, or are there ways to reduce this rate?

So basically what are the best options for me?
Should I seek professional tax advice / get an accountant?

Here is some basic info:-

Full time PAYE at 40% plus NIC paid at source on approx £38,000 + Benefits
Freelance ? ? ? ? on approx £15,000

Legitimate freelance equipment expenses around £20,000.

I have enough money put aside to pay tax at 40% but I’m sure like everybody else on the forum I would like to reduce my tax legally?

Thankyou in advance for the advice