Yes they are down - from my spreadsheets, sometime after the 3:50 at Wolverhampton (never made it to the 4:05 at Ludlow. Twitter is awash of other people saying they are having Betfair problems.
@BetfairHelpdesk say "We're still experiencing disruption to
http://betfair.com . Markets are currently suspended and updates to follow asap. Apologies again."
Hope its back up soon and we can all get back to winning ways!