I think I was being the exact opposite of inconsiderate, friend thinks I was.
In short:
I was on a shopping trip from hell (4 kids wanting school bits) which was unproductive and I was heading back through the department store to the carpark when I saw they had a clarks shoe bit with a sale (empty). I plonked down, asked the assistant if she had ds1 and ds2 size shoes and started to feed whiney velcro baby in order to be heard rather than screamed over. I'm an experienced feeder (top up, other down) and can easily feed strolling around without flashing a nipple though I sat this time with my back to the main walkway. The assistant replied to my request with 'we have a feeding room', I smiled back and said I was fine and asked again for the shoes. She suggested I feed there and popped back, and gave directions, to which I said I knew it was two floors up, full of mothers who are trying to soothe tiny ones who don't need my lot staring at them/ being loud plus I was in a rush. She looked so grumpy getting bits out and affronted by me. I'm not particularly confrontational or particular about bf (I've ebf, mixed and ff equally loved children) but it got my back up a bit. I didn't flash her, was polite, as were the children (though I doubt they would have been stuffed into a small room with nowt to look at) and it was easier for all than listening to a screaming baby.
My sister, mum and friend all maintain it is unreasonable to publically feed unless you must, and stores provide a feeding room so people like me don't take up space feeding or put off others shopping. Yet even the dad on his own didn't look fussed when he came over (I think noone noticed). They say I may have put of business and it's just inconsiderate.