Derek Sheridan's lead sound is amazing, IMO. It's actually extremely simple compared to Jordan's (which I don't like anywhere near as much), but effective. The trick is finding a wah or controllable filter that has the right frequency range. It used a very unique wah off the Korg Trinity that has a totally different frequency sweep and resonance point to a Crybaby or any common wah. Honestly, the only way I've successfully reproduced it is with Korg's own effects (included in Korg Legacy Collection), otherwise it's basically just a sawtooth. Jordan's, on the other hand, is like 7 layers or ROMPLER samples through some fairly specific Kurzweil filters that I can't get close to even on my large bank of software synths. Though maybe I'd try a little harder if I liked it as much.
Sorry for the off topic.
But to echo the original poster, it does sound like a saw modulated by a pulse LFO very quickly. It sounds like a fairly mathematically simple sound, so it should be fairly easy to reproduce with maybe one or two oscillators. It's definitely using 2 detuned oscillators to produce the tone, though, as you can hear the phasing. Very Prophet V.