Hey PintofT,
Im sure there actually 6 exams in mod 1?
4 exams in one day does sound tough but yes thats what most people are doing! Once you get right into the study though you'll see that two of the exams are VFR comms and IFR comms, which arent really much to worry about and very straightforward if you have a PPL and comfortable with RT anyway. During the week long brush up you only spend about an hour overall going over the two of them combined! The other two exams that day day Air Law and Human Performance, both alot more work than the comms papers but after studying, brush up and plenty of time on question bank and the brush up/progress tests you'll be fine!!