Hi
Slightly off topic do you think your enquirers are emailing another 2 or 3 companies.
Dave
some probably are, some probably aren't. odd question
simple and easy is the king with forms, and even better if the form can be sent using ajax so that it's all done without having to move from the page.
drop the how did you find us field imo and install a script to tell you this for every visitor, not just the ones who tell you. then also remove the captcha and see how it goes. if you get a lot of spam try a simpler way to reduce spam, e.g. 1+1 = __? i don't have anything on my forms and never get automated spam from the contact form, just spam through people using my email address.
do you need first line of address on contact form? i can understand postcode so you can ignore if it's out of your area, but 1st line can be a bit long and something you can ask when you call to confirm.
can't really remove any more then that. if email is compulsory then i suggest making it optional as rarley should it be required.
hope this helps