More on the reasons for this site
I've written a condensed version of my reasons for compiling this site on the Home page, but there's more to it than just that. If you're interested:
Mistakes in textbooks, mark schemes and syllabuses
No disrespect to writers of textbooks - they do a tricky job, often in less than ideal circumstances. Debates between exam boards and the DfE at the planning stages mean that syllabus details are rarely finalised until quite close to the start of teaching for a course. The textbook writer(s) are then usually given a fairly short amount of time - I've heard of it being a matter of weeks in some cases - to write the 'approved by the exam board' textbook which, of course, we all want to buy. With this kind of time pressure, it's understandable how errors can slip in. One solution to this is to buy a generic physics textbook (yes, they still exist), but pupils, parents and line managers will often, naively, assume that the 'approved' version must be the best.
A lot of things I try to give a good explanation of on this site are things I've seen explicitly stated in textbooks, mark schemes or syllabuses in either a misleading or downright wrong way.
Questionable Physics in mark schemes
Having been an A-level marker, I know that published mark schemes never contain the last word on what's an acceptable answer as opposed to the ideal answer, but I've still seen wrong Physics given in mark schemes; not just on the 'accept...' or 'condone...' list, but as the first and, sometimes, only response listed on the mark scheme. Teachers, reasonably, look to mark schemes for guidance on how they should teach a topic in terms of how to answer questions ideally, so putting wrong physics in a position which implies it's an ideal answer is making their lives unnecessarily hard.
Again, several things I explain on this site are here specifically because I've seen them badly described in actual A-level exam board mark schemes.
Mistakes in syllabuses?
Syllabuses (or specifications, if you prefer) shouldn't be prey to these sorts of issues, but mistakes still slip in. If you're being charitable, you could perhaps put them down as the result of typos or the convoluted nature of the approval and editorial process. Whatever the reasons, it doesn't seem to stop mistakes or misleading statements of Physics slipping in from time to time.
...and the name?
I invented the name Physicopoeia following the idea of a Pharmacopoeia. These were originally big books containing recipes and directions for making medicines. Once a pharmacist owned a pharmacopoeia, s/he could, in theory, then make any drug s/he wanted. My hope is that this site can act in a vaguely similar way: a one-stop 'how to' guide to things that you might struggle to find elsewhere.