Your conversion is probably more-accurate. I was just going with Google's conversion, but if you compare pricing for currently-available Dyson models in the US and the UK, the conversion-rate is closer to 1:1 after available US discounts.
OP was probably referring to the fact that things sold in the UK are generally more expensive than the US. Something sold in the US for $100 might be £100 in the UK, even though the conversion rate would have you think it should be £60.