Had a quick look on there website and could not see it there. It doesn't say its invite only in the T&C's.
Saynoto0845.com Number for Edgbaston: 0121 4465506
Join the half term fun at Edgbaston on Tuesday 26th when England play the West Indies. Andrew Strauss and his team come to Birmingham for the 2nd match in the 3 match series and with the Ashes summer looming everyone will be wanting to impress. Extend your Bank Holiday weekend and take advantage of an exclusive offer brought to you by Inside Edg during this fantastic summer of cricket. Buy One ticket for this match at £55 for adults and £20 for kids and receive another absolutely FREE.
To redeem this offer call the Edgbaston Ticket Office on 0870 062 1902 and press option 1 and quote IEODI09 to get your tickets today. Offer valid until Wed 20th May and the following terms and conditions apply.1.This offer cannot be used in conjunction with any other offer.2.Tickets purchased before this date do not qualify for the offer.3. If a Junior ticket is purchased a free junior ticket will be offered.