Still a hint, Smellyharry. I stand by my earlier comment. But there's no need to apologise to me. I'm only expressing my view, which may we be a minority one. The poster put the same request on at least one other site. Finding the way in is the hardest part of many numericals, so I think one needs to be cautious. As for clarifying the preamble, I have more sympathy, but the questioner conceded they thought it pretty much had to be that. Why did they not work on that assumption and see if it bore fruit?
To me the natural approach, and the only way to become a better solver, is to try as hard as possible to solve unaided, and only come here when one has reached a complete dead-end, not seek validation or help before even attempting it. Anyway, I've said my piece. I'll shut up.