Because of Albufera32's comment, I went to look at my messages, to see if there were any ticks - and there were. However, even better there was a new message, the first unsolicited contact for many months probably 6 months any way. I spent some time answering the query ( I did have lots of info I could give to the sender), and unbelievably I noticed I had another new message.
This one was in reply to a message I sent. I sent it on 18/12/2019, and she replied 18/12/20. I never cease to be amazed, but it is true, don't ever assume you won't get an answer, just because the recipient doesnt reply straight away!
As it happens, it was a very short message but the sender did supply vital information about an NPE, confirming the biological father to be someone other than the surname given in their tree, and the same name I had given in my original contact. I think showing you have done your research (as opposed to just 'fishing'), helps you to get a response, even if it might be delayed for a year or so!!
Jane