Welcome to the forum Jordan.
You haven't mentioned the nature of your 18 months experience in the NHS.
But, assuming that you are now in a biomed department of reasonable size, and therefore in a position to be mentored by veteran technicians ... and
are keen and willing to watch, listen, and learn ... then you may not need to return to college.
But you should still expect to be at the bottom of the heap when it comes to pay banding, I would have thought. After all, we all have to start somewhere.
After that, it's up to you. Do you want to be "hands-on" ... or do you have other aspirations? Personally, I would recommend the former.