Alan
Generally agree with the above comments - hope you're taking them as constructive critiques! Just to add my two-penneth; the design's a bit busy, with some real inconsistencies - drop shadows on some text boxes but not on others, for example. Personally, I'd also choose a less 'florid' font as the main masthead - it'd be fine in print if that's the 'look' you're going for, but on a screen the fine lines can't be resolved properly and just look jagged. I'd also be inclined to use fewer fonts and colours as they tend to distract from what you're trying to say.
From a purely practical standpoint using Flash for navigation elements is generally frowned upon, and is definitely a bad idea if you don't provide html links as an alternative - anyone without Flash, or with Flash turned off can still find your site, but won't be able to navigate around it.
From a technical point of view the photos don't always show your work in the best light; I was a photographer for 20-odd years before turning to the splintery side of things so I do understand how hard it can be to take a decent picture of the job when it's at the end of the working day, you've just cleared up and need to get home to empty the van and start on the paperwork, but you have to remember that after the job's been designed, made and installed the photos are all you'll have left to show people; they have to be as good as you can make them, and if that means arranging with the customer to make a return visit during daylight hours to take a couple of decent snaps, then that's what you have to do. I'd also suggest you to try and avoid taking pictures with direct flash as the specular highlight is not only distracting but it can make the finish on some work look patchy and inconsistent, even when it looks fine in real life. Not everyone can (or wants to be able to) take a decent picture - as ETV says above, can you rope in a mate who's a keen snapper to do some shots that reflect the quality of your work?
There's a couple of other little design things - you're listing a contact email address, but haven't put in a 'mailto:' link, yet you're using a form for customers to contact you which is usually what you do to avoid putting your email address on the site so it doesn't get harvested by spambots... Also, why an @ntlworld.com email addy instead of @alanwilley.co.uk? And no contact address? Pretty sure it's been a requirement since about 2001 for all commercial websites in the UK to have a full address listed somewhere on the site - doesn't have to be big, or in a bold font, but it's definitely supposed to be there.
Hope this helps, Pete.