Whoops, sorry for causing a stir. To make up for my comments I have done a mini literature review for you.
This website describes first seizures well and talks about what could be the cause, explains investigations including other causes of collapses that will be considered.
The epilepsy society website talks about "epilepsy". "Epilepsy" is usually defined as having had more than one fit rather than just a single seizure. This is because single seizures are common and not all people (particularly those with normal scans) go on to have a second. So some of the information is not relevant after just one seizure. But it has info about driving, sport, first aid, medication and avoiding seizures, what you can do etc. and a phone number 9-4pm 01494 601 400.
I'm really pleased you got your investigations and saw a specialist quickly. They remain best placed to give you individual advice regarding diagnosis and your chances of having further seizures. This will help you decide what to do about biking. Your GP (when they get all the details) will be able to advise if you want a quick answer.
But as everyone on here says, don't panic! This is a common thing to happen and you appear to have taken in much more information that most people do the first time they see a doctor!
Practical advice: are you in the UK? If so: you get a free bus pass if you can't drive (not really much of a replacement, but hey, you may as well use it). You should request your license back from the DVLA in 3 months. Sometimes for a single seizure they let you drive again after 6 months and it takes 3 months for them to get it sorted.