Good evening, I am having a lot of trouble with Level 469 - Code: GKPHGHLLLOHOLKKHGIGN - this level has no raise or lower land, only abilities other than yellow are basalt and tidal wave.

I am continually losing due to my leader not being able to move off it's initial island, I have to play with ultra slow speed in order to build basalt roads to try and get the leader into the middle of the map, losing vast amounts of other units on the way as they die from attrition.

Next play through attempt, I will obviously be noting down every code so if I hit a level I find impossible I can replay it for a different score and thus a different follow up level - just hoping someone knows this game enough to have any hints for this map as I'm dreading playing the first few 50 odd levels again to get this far.

This will teach me for not noting down every code between levels!

Well firstly, the code for level 469 is ITLDAD. It looks like you've been writing down the code that saves your god, which is not the same as the level code. A list of level codes can be found on Gamefaqs here:
http://www.gamefaqs.com/pc/564733-populous-ii-trials-of-the-olympian-gods/cheats

The difference is that your god code appears on the screen where you customise your god, while the level code appears on the screen that describes the next level and shows what spells you will be able to cast.

Anyway, the first thing to do is put your followers in 'go to papal magnet mode'. This will cause them to bunch up and combine, so there will be less deaths through exhaustion. You lose mana when your followers die, so this will help you cast. Place a basalt bridge as soon as you can to get your leader off his island. Move the papal magnet around to guide him, don't try spamming basalt as you won't have the mana.

Once you get onto the main island, move the papal magnet onto every enemy house to make your leader conquer it. Most of the time the leader will remain in his house when you move the magnet and you will need to right click on the house to make him leave it. You can sometimes speed it up by going into fight mode or making a hero, but fight mode doesn't seem to work as well as it should and heroes destroy the buildings they conquer so you should not use them until you have a decent population.

Cheers. I understand the difference between the Codes. Hence: "This will teach me for not noting down every code between levels!"

Unfortunately, I have only twice managed to get the leader off the initial island, the path finding is so bad he gets stuck in a corner somewhere, or dies from attrition before the as you mentioned limited basalt path gets completed.

Anyway, I think you have the solution for when the terrible path finding allows me to actually get off the island - I usually use Combat mode and I think I've been shooting myself in the foot by not retaining lands. I'll definitely have to give that a go. So thank you for that.

Or just start over again and get a different score to avoid this terrible level :)