Hello!
Sorry, this reply is a little bit late, I only signed up myself a few days ago, I am currently in year 13 at Canon Slade and I applied as an external student. At the start of the year, I actually stood up and gave a mini-presentation to possible applicants, so I am not sure if you were there that day, if you were, it's great to see you again! Let me try and sum some things up, this time I won't have the pressure of members of staff standing behind me, haha.
I studied chemistry, maths and history at Canon Slade.
I applied from an external high school and got in (they have to accept at least 18 (this number may be different for your year of entry) students from external places but this is not a maximum they will accept). I went to a school that was, let's say, very different to Canon Slade and I was the only person who went to Canon Slade from my high school.
I found most members of staff to be both encouraging and friendly, although there are and always will be a few exceptions. I also found the application less stressful than I initially imagined, the face-to-face interview was friendly and light, with very little pressure. The "golden star" in the sixth form, in my opinion, is Dr Eves and Mrs Howarth-Pash. Dr Eves first of all is the head of sixth form and is a physics teacher. He is honestly the most knowledgeable and friendly teacher I have ever met. He knows everyone in sixth form by name and even passing him on the corridor he will say hi and smile most times. Mrs Howarth is a non-teaching member of staff and handles a lot of admin, but is also there to be a friendly face, should you need someone to talk to. You can stop by her room any time of the day if you need a chat or have a question/concern. At one point, I needed to file a report (I won't disclose the details) but she was both encouraging and cooperative in seeking a solution. Other than these members of staff, you will have a dedicated head of year as well as several other pastoral assistants (who are teaching members of staff) to aid in both academic and personal needs in sixth form.
Overall, I found the teaching to be very good, I don't have any experience in bio or psych I'm afraid, but I know the current psych teacher is fantastic! In my experience, chem has been very good overall, as well as history. The maths side of things has been a little more shakey, especially when it comes to the department setting mocks, that are often unfairly hard with high-grade boundaries (far harder than the real A-Levels), but since you are not planning to do math, this shouldn't be a concern.
The one area that I may not have been entirely truthful in my mini-presentation was the social side of things. Let me just preface this by saying I am VERY introverted, and find making friends very hard, so just keep that in mind. I found making friends very difficult, and I spent both 2 years sitting alone, for the majority of the time. This is mainly due to the fact that established friendship groups that were built over 5 years of high school, carry over into the sixth form. I found it both awkward and stressful trying to fit in and to be honest, I do question if I ever really did fit in. To be fair, this could just be as much my fault, as it is the environment, I know other external students have fit in very well, and honestly, you can't tell who was external and who was internal in 99% of the situations, especially by the end of year 13.
I hope this helps, sorry it was so late!
If you have any more questions, or if anyone else does, I would be happy to answer!
Good luck with your GCSEs!!