Thanks guys.

Unfortunately I'm pretty burned out with this right now so I won't be rushing through an update like I intended. I had considered cutting down the area of the map and rattling off a quick sunken version so I had a proper entry into the challenge but I've come to the conclusion that if I did that then my motivation to carry on with it and finish it like I intended would drop off. So I guess that last image I posted will be my unsunk entry. Hehe. Sorry I couldn't get this done in time. Missing the first week of the challenge, the kids being off school for a week, a short month and my utter inability to go above a snail's pace have done me in.
Anyway, I intend to carry on working on this as I am enjoying it but I will now finish at my own pace. So expect it in about a year's time.

Good luck to everyone who has entered the challenge this month - there are quite a few worthy entries and it will be interesting to see how the voting goes.