I canít remember exactly what he has but it was 2 battalions with Cawl, Tech Priest Dominus as his 2 main HQs.
Keep in mind if he has no other HQ's than his list may very well not be legal. Each battalion must have two HQ's.
Troops was 6 5?man skitari squads. 2 squads of Robots (4 total). 2 Dunecrawlers with neutron lasers that just killed me. 10 electro priests , 3 breachers and 5 Sicarian Infiltrators. Think thatís it.
That would pretty much have to be it, beyond needing two more HQ's this is around 1900 points worth of stuff without any upgrades (beyond the neutron lasers.)
At present Iím just kitting my army out with as many lascannons as possible to take out his heavy armour whilst using characters to buff the roles. I find that unless I destroy either one Dunecrawler or 1 squad of robots during turn 1 if I go first I really struggle.
Sounds like you need to focus on overwhelming firepower and controlling fire lanes.
That being said, hellblasters, super charged plasma, melta weapons, and anything that can do a flat 2-3 damage are best.
Especially with is invulnerable saves.
Barring any canticles that improve invulnerable saves, his army is only rocking ++5 and ++6 saves. Now if he is using the Lucius forgeworld dogma than he gets to treat -1 ap weapons as 0 ap, but that has no bearing on invulnerable saves.
Last time he deployed 1 Dunecrawler and One Squad of robots plus two squads of on either flank.
That actually sounds like really bad deployment for the dunecrawlers, since they would get to reroll saves of 1 when close together. Also by doing that he cannot guarantee that both groups will be able to shoot at stuff, unless you both play on a fairly open board.
I deployed my Pedator (with Cronus)
This part of your list is actually illegal. Chronus's vehicle needs to be purchased separate to that predator you've taken. So that detachment would need another heavy support choice if he's going in the predator.
The Landraider got taken out in turn 1 by three neutron laser hits.
Were the neutron lasers the only thing that damaged your land raider? Because if yes those were some really lucky damage roles; near perfect in fact. To burn through all 16 wounds.
Could you flesh out your list a bit more, that way we can get an idea of what your loadouts are. By the way are you using the codex or the index?