I did HNC and D in Building Services Engineering, i learned a lot, but ferk me the maths was mind blowing and total waste of time, its bums on seats to keep academics in a teaching job for the most part, the guy who taught us electrical modules couldnt even get BS7671 right but argue with him at your peril , not being as knowledgeable at other services it made me wonder just how good the others were, that said i can now contribute to loads of subject areas and offer non electrical solutions where it is the right choice.
I'm no natural academic and doing assignments every night for 3 years wasnt fun, and in my line of work got me no extra cash and no extra respect from management, depends how old you are and what your domestic situation is lets just say my other half at the time couldnt do with the amount of time it took.
Some careful thought needed.
HNC got me a job as a surveyor , about 30K top - so set up company to supplment wage lol