Whatever you try to do, the British weather will screw you. The best option is to do a PPL in 4 weeks. Take two weeks leave, go to somewhere sunny in US and learn the basics, then go back a few months later to finish off. You will get a PPL much quicker and easier if you can do it in as short a period as possible. If you get the PPL part time it could take you a year and you'll use way more hours than you otherwise would. Eveyone wants to fly at weekends which means you'll be fighting every time to book a flight and even when you pre book lessons you might only fly 1 in 3 due to weather. Once you have a PPL you can concentrate on studying for the ATPL exams and hour build as and when. You can use your leave allowance for the following year to get your IRR, CBIR, MEP etc...