SUCCESS!!! What a relief! I can hardly believe it!
I was writing back to say it half worked, when I remembered I'd plugged the ethernet cable into the motherboard, so I plugged it back into the rlt card, never expecting it to work yet! But it did! LOL!
I don't suppose it'll be trouble free from now but it feels like a big step forward!
thanks i92guboj, schneidz, jschiwal, thumberlina, for all your help; much appreciated.