OK I can help, but you would first have to tell me the company in the US, the company you had the price from in the UK, the product, the way you would have it shipped, the insurance on the shippinjg (as per the $ value) and your method of payment.
Remember one thing. The dollar has dropped 30% agains the pound in the last 10 months - 1.5 is now 1.88.
The english company you are getting quotes from either has a dollar account that they buy with, or they pay in pounds at a given exchange rate. The rate they got is unlikely to be the rate today. If they bought in Feb, they would need to be 30% more expensive to get the same amount of money.
If the company has a $ account, what rate did they buy at?
My point is that the UK firm could have paid up to 30% more in the exchange. They would also have had to pay 17.5 % out on delivery (they can claim this back at the end of the year) and other business taxes that are specific to 'business to business' transactions. As an individual you do not pay these fee's as it is supposed to be a retail sale with taxes included.
On top of this the UK business prolly wants to make money. They spent time and effort to get the gear sent over to sell. If they can't sell at a profit then what is the point. Your internet/mail order guy in the states is a totally different animal, they are into selling volume and often they won't even have the goods in stock when you buy it.
Also there is the matter of warranty. A UK form will likely offer a warranty with the product, you will not get this from a website in the US.
The bottom line is that the UK store business is not a healthy one, because people grey import. Because of this they need to charge more to stay alive. When they charge more, more people grey import. If the UK scene was to disappear and you suddenly had to get everything from the US, you would prolly not be impressed.
Either way the UK store loses out. If the business was healthy and people were buying volume, the prices would drop (this is what happened in the states2-3 years ago)
Hope this helps, I wasn't sneering.