Hi EmbraerAhoy
I concur with redsnail's post.
You might be underestimating the amount of work on integrated course particularly during the ATPL theory phase. As redsnail stated mostly useless but it's a lot of volume in a short period of time & successful students (first time passes with good %) are the ones 110% committed to this with no distractions or emotional baggage holding them back. Though it would be good to continue to work part-time I am not sure you will be able to SUCCESSFULLY do both, as it's full-time day classes with most students doing several hours extra homework. You might find yourself getting (justifiably) annoyed with the standard of the exams but you need to treat it as an entrance exam to becoming a pilot, as said before most of which you'll never use/see again.
As a former ATPL theory instructor I found the biggest hurdle for most UK students was basic maths. I strongly advise you to spend your time getting used to transposing formula eg. distance/speed/time, interpolating graphs & tables of data, basic mental arithmetic (in 2020 EASA introduced mental dead reckoning into the general navigation syllabus). Also some knowledge of physics gas laws would be useful. GCSE/secondary school level should be good enough, you don't need differential calculus! Years ago ATOs often used the first week to revise all this material but no doubt due to cost sadly no longer.
Best of luck.