Bluesquare seems to be very generous with their reloads. Since joining, I've found a £5 free bet in my account each week in addition to those I expected from the initial offer and the Wimbledon/Open/Goodwood offer. And this is in spite of my accidentally winning there a couple of times and withdrawing.
Could be worth checking if you haven't looked at them for a while. but they do have a short shelf-life (7 days) so look in weekly!