Okay, no one seems to really be answering your question so here goes:
The UK is like nearly every other first world country. There will be the highly educated, the not-so-educated and the averagely educated inbetween. This will vary from area to area. You'll find the same thing in Ireland, France, the United States and Japan.
You get stupid people everywhere but many smart people too. For example, my dad has a degree but my mother doesn't. Someone such as yourself who doesn't know them personally would instantly assume my mother is the more 'stupid' one when really, she's a very intelligent woman.
Also, what would you class as educated? Are we talking socially or academically or? I mean, the UK has free healthcare. Some British universities are amongst the top in the world and in certain parts of the UK you can go to college for free. Socially, the UK aren't too behind.
The whole 'boys like blue/girls like pink' thing is a mystery to me. I've come across two people with that firm mindset and they were from France and the States. As for being resentful and ignorant about the LGBT community I'd say that is more of a generation divide than an education divide. In saying that, you will ALWAYS find idiots no matter where you go.
TDLR; no, the UK isn't under-educated but it could be improved. It's like everywhere else - made up of both smart and dumb people.