Only just noticed this thread and obviously you are all fixed up now, but for anybody else who needs a flat windscreen here is my CJ story (from March)...
I went to a couple of "plant glass" suppliers, and they wouldn't do it because their glass was not stamped as suitable for "on road" Windscreens.
Went to "Uroglass" who are a specialist windscreen supplier for all makes and discovered that what they really want to do is sell you a screen for your 1970 Lamborghini for £2,800, and were not interested in a CJ7. (by that time, neither was I...).
Went to the local Autoglass depot. Receptionist / telesales people had no idea so I explained to the manager. They cut down a Landrover Defender windscreen (being careful to leave the stamp...) and did it for £80 + VAT fitted.
John