By unofficial, I will assume that you mean stations whose WMO numbers begin with 99 instead of 03 such as the botanic gardens in Edinburgh and the downside here is that you can only get data for those stations for the last week, although even that is more than you would get elsewhere.
Although the botanic gardens in Edinburgh is still classed as a Met Office station, it seems to have lost that status by quite a lot as such over recent years and fallen more into the shadow of nearby Edinburgh Gogarbank which is an official station with a WMO number that starts with 03..
In fact, the botanic gardens in Edinburgh's own website used to be really good at publicly supplying summaries of all of its past data from 2009 onwards. However, they stopped providing access to that data at the beginning of the COVID-19 pandemic back in 2020 and since then, they have also removed all of the links to that past data.
Luckily, I was able to grab that data at an earlier time when I was able to do so and thus, use that for my various reports on this forum. Because of that, I still have that data on my own systems.
Had I not done that back then and had I now been looking for that data, there is no currently no way which I know of, of being able to get that data and I think that it is so sad that this has now become the case.
Originally Posted by: johncs2016