My co-worker is off sick (how sick? He's in bed with his sister! HAW HAW) so I threw caution to the wind and set about dismantling the somewhat sad Glass Mountain. Two farm towers (melon and pumpkin) are thrust up through it and as it is dwarfed by all around it and since I tidied up that area, it's looks somewhat sad.
Leaving just the towers! I used a silk touch pickaxe, so managed to recover 17 stacks of glass, which is handy. I started messing about with tidying up the ground (which is very satisfying) but stopped short to ask @EMW a question: may I chop the tops of the farms off? If OK, then it leaves a prime bit of building land and the towers would be entirely underground. If no, then that's cool, I'll dress them up.