PPL to ATPL is quiet a leap in both theory and flying standards. That said the ATPL exams leading to a CPL/IR (Frozen ATPL) are achievable by the majority of well motivated, financed and determined students.
Your degree shows learning and problem solving ability so this shall have an indirect but positive bearing. Also degrees open doors to other options should plan A not work out.
With a PPL and 145 hours, in my opinion you are wasting & duplicating effort going for an integrated course, unless you get "sponsored". Just get on with a modular course/route after getting your Class 1 medical at Gatwick.
Your next decision is either full-time or distance learning tuition. You need to check out all the potential providers, you normally get what you pay for. Visit the Flyer show at LHR in early November.
Both methods have their good and bad points. I have done both methods and in my opinion if you can take the financial hit of not working for 6 months I would go full-time every time. Easy and direct access to instructor, feed off other students. Of course everyone is different and you must do what is right for you. I suggest you keep your pre-course revision to the PPL books, Met underpins everything in aviation so start there. Your course provider should provide all the required training material. Make sure you are an EXPERT with the CRP-5 whiz wheel.
Please free to PM me if required.