Thanks Angela and other JY'ers.
I am back from the capital now, and it did me good on a few levels. I am focusing on booking my first JY tour as a stepping stone, sort of, into solo holidays - I have some time so probably won't book until at some point next month, I don't want to rush and risk anxiety thwarting me again.
It occurs to me that to get to Paris in fact over laps with London in that I have to get to London Paddington (done) and across to St Pancreas before meeting up the JY rep and fellow travellers and boarding the Eurostar. I don't know to what extent I will require the JY tour manager and local guide as I don't know how I will respond to the new, unfamiliar city but then who does until they do it and take the plunge?
I think for me, the only point where a rep/tour manager could be worth their weight in gold is at the commencement of the trip (St Pancreas, or Heathrow if I do one later in the year) and making sure I adhere to the right process and procedure and get in the right queue. I'll likely pick up a map and guide book in advance, just in case I feel brave enough to make it a truly solo trip - jury's still out on that.
Thanks JY'ers, I'll keep in touch with this board - never know what interesting gem of information you might come across.