The typical asking rate per listing is in the $30's per square foot per year. The Heathrow region is going through a a boost in rates. In the last 3 months, the median rate increased $6 per sqft per year. That's a 22% increase in rent.
In the last 90 days, 3 listings have been posted online, which means new listings are probably going fast. You'll want to be prepared to make an offer immediately. About 233% of the office spaces in the Heathrow are subleases, so you might be able to find a shorter term or below market rent. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 7,080 sqft, there are still 0 new availabilities below 2,000 sqft. Most buildings in this market are close to 3 floors. Most buildings in this market were built in 1997 and are Class A.