I kinda wondered the same thing if it would be as interesting, its hard to answer. I got interested in physics from films, tv and documentaries. As long as you have an interest in that and the spark of curiosity is there, the mathematical concepts and physical laws will intrigue you (unlikely all will appeal to you) and you get a appreciation of just how clever they are as the course goes on.
I dont think level 1 covers much detail of what you just asked about, All Science degrees with OU share the same level 1 60 credit science module, it was called S104 when I done it, it was basically a very well written crash course in GCSE/Alevel Biology,Chemistry and Physics. People complained it contained too much content and it was changed dramatically this year or last year and is now called S111. You could do this compulsory module alongside the physics required module MST124 comfortably. 90 credits of level 1 in one year is very doable, even if you haven't had the A-levels. These modules really do start at the uttermost basic level and it would shorten your degree time down.
I studied 120 credits level 1 credits in a year and then the following year 120 level 2 credits, both years alongside a full time job. Arguably I should have only done 90 level 2 credits in my second year, because 120 at level 2 was a lot with a full time job, but I got through it. I think its worth doing 90 level 1 credits, MST124 will complement the level S111 module.... and MST124 goes well beyond the scope of maths used in S111, so you wont be playing catchup.
I dont particularly like Quantum Mechanics. The maths involved at undergraduate level is relatively straight forward, its a branch of maths called linear algebra. Its covered in MST224 (maybe renamed) and the maths is again refreshed in the QM modules books.
I cant stress this enough, if you look at physics content thats beyond your current understanding its really intimidating, well it was for me and still is! I questioned whether I would even get some parts, But you build up to it if you put the hours in.
Another link for visualising maths and physics concepts
https://www.youtube.com/user/EugeneKhutoryansky/playlists (its probably the best, dont know why i missed it off my first post)