Sound like you’ve given up? 4 months should be easily achievable in summer. Simulators work in all weather, which leaves 15 hours IR and 15 hours CPL training. You might be reading too much into things, training in the UK is all very noble, but a plane is a plane, the laws of physics remain the same, so it’s only the charts that look a bit different and your radio work should be fine. Everything you need will be taught on the courses so hour building abroad is fine. A CPL test is just a bit of navigation, some instruments, some handling and some landings, all of which you’ve done for PPL. Course-wise, you need to average 15 minutes flight time per day. Only half needs to be VMC. So any weather excuse is nonsense.
Another thing to consider is doing an SEIR - shorter, cheaper and no need to do the MEP first. If time is short and you need to ‘save’ the atpls, it’s the best option. You can upgrade to MEIR after your exams expire.