Here's a bit more information about having SEO work done to your website.
One-Off Payment
It is a one-off payment for a one-off job. I am not offering an on-going SEO campaign. I am offering an analysis of your current site to indentify and fix specific ways with which your website's SEO could be improved.
Think of it like taking your car to a garage before an all-important street race. The mechanic looks over your vehicle and fixes any problems he finds so that the car runs more smoothly and more efficiently. He may also add things to the car which make it more powerful and more responsive. After he's done the work you drive away with a better chance of winning the race than when you arrived.
I'm the mechanic and your website is the car. I will fix and improve every content-based issue I find on your site for which I have access.
Please Note: There are some potential problems which I wouldn't be able to fix due to not having enough access, or due to it being a major job. For example, if the layout of your site is a complete mess or your navigation is rendered in Flash that would require a complete overhaul of your site to fix. For big problems like this I will report them to you and give you a list of options for how best to get them fixed.
Dave's Disclaimer
Due to the nature of SEO I can't guarantee any specific improvements in your Search Engine rankings based on the work that I do. However there is no reason why the work that I do won't improve your site's rankings. Going back to the mechanic and car analogy, a mechanic can't guarantee that your car will win the race but he can definitely say that changing its oil and repairing its broken exhaust pipe will improve its chances of winning the race. At the very least the car will drive faster than before.
It seems pretty obvious but I feel the need to state that, just in case someone presumes that for £180 of SEO work they'll magically appear at the top of Google by tomorrow afternoon.