Hi Rach and welcome to orchid board from a fellow Brit
Personally if unsure I usually post stuff in the 'beginner discussion'. It's a good general place to put something when you are not sure the best place.
Perhaps as a moderator of this forum I should be able to give you better directions than that, but as a moderator I can tell you that we don't really mind too much where you post something, we are very relaxed here.
.
We may move something if it's not getting many answers and we think it would get more in a different place. Also we may move a post if it's obviously in the wrong alliance sub-forum (like a question about a Phal in the Catt alliance section or something), but again that's more to help you get answers than anything else.
Don't worry about posting in the wrong place, it's better to ask your question somewhere rather than not at all.