Nah online is pointless. Guys are only after 1 thing. Sex chat and pictures to wank over. The way we done it after she finally agreed was join a swingers website. Your in the uk same as us. Join fabswingers. We chatted in the chat rooms, replied on forums, sent messages etc... We had hundreds of men messaging us. It was to much. In the end we blocked single men and only chatted to couples. One couple stood out for us and we agreed to meet them at a swingers club in kent. They showed us around and sat with us all night chatting which helped alot. Questions we had, any doubts we had. All answered. It wasn't until the 4th time out that we actually played. Even then it was girl on girl. Turns out the wife is Bi and she likes playing with women. She has not done anything with another guy yet apart from wank him off a bit.
My wife suffered with anxiety so a club was hard for her but it was alot easier doing that than meeting some random Off the net for a quick shag.
Clubs are relaxed and that way you get to know people better in person rather than by text online. Also you can always so no even if you arrange to meet a guy in the club and he turns out not the way he is online you can say no.