By my reckoning there are 7 ways up Leith Hill (by road - MTBers have plenty more options).
1. Coldharbour lane
2. Henhurst Cross/Anstie Lane
3. Broomehall road
4. Leith Hill Road
5. Tanhurst Lane
6. Hollow Lane/Leith Hill Road
7. Sheephouse Lane/Leith Hill Road
There are a couple of sub-variations like Logmore/Coldharbour or from Holmbury via Pasture Lane but it could get silly.
Anyhow, why not have a Club des Cinglés de Leith? Like the Ventoux version, all you have to do is prove that you've ridden all the routes up there in a single day.
The advanced version includes a pint at The Plough in Coldharbour after each ascent.
Who wants to be the first to try it? I will give it a go once I'm fit to ride again.