I don't think I've heard of a postgrad pharmacy entry point before (for the UK anyway). You'd have to search around for it, but I'm not sure it exists.
I'm pretty sure undergrad pharmacy is not an exception course eligible for second degree funding though (unlike e.g. nursing or physiotherapy and similar things).
If you change course/uni, what happens with your current SFE funding is a bit complicated...
Basically the calculation is "length of degree + 1 year - number of years in higher education", where "length of degree" is the length (remaining) of the new course. It's very unlikely you will be able to "transfer" into second year or above for a pharmacy degree - you would essentially just be reapplying for first year entry.
What this means is, if you have more than one year on a degree course elsewhere, you will start needing to self fund tuition fees (you still get a maintenance loan) at the new uni for each year you had prior study for. Note also, the self funded years come first, so if you would apply after 2 years in a BMS degree to first year in a 4 year pharmacy degree, you would need to self fund tuition fees for your first year there - you can't "put it off" until final year to save up in the meantime, unfortunately.
Thus ultimately, you should never, ever start a degree you don't intend to finish. It becomes extremely complicated and expensive to the point of preventing you actually getting a degree if you do so in the wrong timeframe. If you want to do pharmacy, and you aren't on a degree yet, you should take however many gap years are needed to get onto your desired course. If you are already on another course, if you've finished first year but not yet started second year, you should withdraw now before starting second year, and then reapply in the coming application cycle.