Queen Mary's or Surrey for Theoretical Physics

League tables are pretty much meaningless in this circumstance - if you're looking at any differences smaller than 10+ "spots" between universities, the metrics are just not useful in discriminating between those. The rankings are too volatile and differences too small to infer anything meaningful from that situation; rankings are more useful in the broadest strokes e.g. UCL is generally considered stronger than UEA in many subjects, and both are considered better than e.g. Solent in most subjects, to get an idea of where things lie on the largest scale.

If you like Surrey, then that suffices in of itself. It's better to go somewhere you like more, regardless of how tailored the course is to your current idea of what you want to do, than to go somewhere else which is the perfect preparation for one possibility of a future, and end up hating it. I would say my impression is QMUL is better for TP than Surrey, as the latter seems to focus more on the industrial/applied side of nuclear physics and imaging (their theory work seems more focused into their Maths department, although it's likely they contribute to UG teaching in Physics). But I couldn't say confidently the difference is enough to be worth choosing one over the over. Brian Wecht was a pretty notable figure at QMUL but he did leave to be a full time youtuber dressing up as a ninja and playing a keytar...

there's one more thing if Surrey is the last uni left and the others don't consider should I pick it instead of a gap year ?