It worked! Lando sent me the "ads.prg" which the game loads after loading the main part.
For those technically interested: Roy were right, it copied (originally) data to $0800-$0fff (colour and screen memory) but then right at the start ($2111) it copied it to the area starting from $0400. You can't do this from plain BASIC, since it overwrites the ROM paging routines...
What I did, is just simply put it over $4000 and changed the code at $2111 to read data from there. And that's all.
I sent the game to Lando, so expect him to put it on site real soon now!!
