Wow, thanks for all the interest - I didn't expect so much for a singlespeed attempt!
Yup, gear was 32:21 on 29" wheels - about the same as 32:19 on 26". I was tempted to go even lower but Rory suggested as conditions were so good to stick with 32:21.
Sorry the GPS tracker packed up just before the finish - the charger refused to recharge a partially-discharged battery the night before so I just hoped it would last. Seems I should have ridden 20 minutes quicker!
IWH, the tracker is a homebrew add-on for a Garmin eTrex - there's a link to the detail in some of the earlier BM stories, try Dave's ride in the MaXx Exposure last year. Also a CX bike is fine - no-one said anything about what sort of bikes are and aren't allowed - the only distinction made to date is whether the bike is geared or not (wheel size, suspension etc - it's your choice, pick whatever you feel is the tool for the job).
On the MaXx Exposure last year there was one guy - Nigel Foskett I think - on a drop bar CX bike and a couple of guys on a tandem (they stacked it on a descent though). So it's clearly possible.
Mike Cotty counted all the gates on a one-way ride and reckons 97. However, it varies a bit because some farm gates are in use or not depends on time of year and stuff.
quinny: I walked that climb from the A27 (and plenty of others) - no pain involved! 
Cheers all!
