im doing the same course at college and got all the books you,ll need for the Course both L2 and L3 on my PC
the books ive got are
both Trevor Linsley,s Basic & Advanced Electrical Installation Work books plus both Basic & Advanced electrical installation Calculations Books.
also got the IEE 17th Edition Guide to the Wiring Regs
theres is another good book to get which is the JTL books as they also show you how to do the Practical side of the Course i dont have that book so i borrowed it from College