Hi David. Have you rode the HEX lately? Here's the Web site link:

https://www.heathrowexpress.com/content.asp?SID={471E9238-25C6-4020-B963-117631F53D48}&pageid=30

It says return is £28.00 in express (second) class if you buy in advance on the Net or £29.00 if buy at a ticket machine at the station. And since one pound is $2.04 right now I don't think you are going to get much change back from $60.

And I'd love to know where you can book a taxi in advance that would charge £30 for the trip from Heathrow to Central London. Don't get me wrong, I love London, just the prices definitely put a damper on things if you are based in U.S. dollars.