Finding FULL spec of your bike

[DaveM]

Your point about having problems if you don't use "compatible" parts is very true. I think nfmisso's point is that "compatible" is not the same as "identical". Unfortunately, it's not always clear what's compatible with what until you have some experience.

Parts lists on bikes are subject to change even during the middle of a production model year. Companies will sometimes switch which parts they use due to cost, availability, supply chain issues, etc. etc. They probably don't like to publish detailed parts lists because anyone who gets a bike with slightly different parts could argue that they didn't get what they paid for, etc. It would also be hard for the company to know which particular version of a bike you have without a lot of research into which production batch went to what retailer. They're not going to spend a couple hours verifying exactly which derailleur you have when you can just look at it. The other issue is that what the bike was built with may no longer be available is the exact same form anyway. So you will still have to work out what is compatible (you can't ask for "a cassette compatible with Tiagra from 2009", that just not how people categorize parts.)

I would try contacting Boardman or the dealer. If you just ask for a comprehensive list of every part, I doubt they'll have that (though you never know). But if you ask some specific questions (bottom bracket dimensions are a useful thing to know) they may give you some details. Seems like the bottom bracket is pretty much the only major part that isn't easily inspected for identification.

Part compatibility on bikes is a big hassle and the manufacturers don't make it as easy as they could to know what goes with what. But a little experience, research online, and time asking questions on forums like this usually steers you right.