Thanks for the advice, I did what you said and
success! 
Now this map is near completion. I don't have any screenshots, but I've done some practise games and it is looking good so far, just need to fix radar trigger, and maybe something else, though I don't know what.
I'll see if I can do some screen shots soon, then have it ready for download!
This will not be the last map I'll do, there are more in the pipe line, including that volcano one, but apart from that, not much will be in WIP topics. Instead they will be part of finished (or, if I am lucky, stoplighted
) maps.