That's the strange thing, I know rationally I'm being reasonable asking this stuff. But there's still this deep-seated part of me that says "Nice girls (and it is gendered) don't make a fuss, they don't complain and put other people out for their own whims". And so the struggle is partly internal, within myself, to say "No, I am the client, this is my money, and I am paying so I get to call the shots". I am not used to inhabiting that position, I don't come from that kind of background, and though I'm now a middle class professional woman on the outside, I'm still don't-get-above-yourself working class on the inside. So I'm fighting within myself, and also dealing with delivering a difficult message outside, to the builder, at the same time, and it all feels very confusing and conflicted, and I don't feel like I know who I am or how to be. 
Wow, I actually didn't even realise that was why I was feeling so bad before I went down this trail this morning. Thanks for listening, guys!
Anyway, getting back to nuts and bolts, the electrician has proudly presented me with two LED light strips. He said he got a "great deal" and the seller gave him two colour changing ones for the same price as the white ones. I don't really want colour changing lights, I just want warm white! I'm seriously hoping I can take them off disco mode, in which they flash violently through a rainbow of different colours (threatening to send everybody in the room into an epileptic fit in the process), and set them instead to one colour!! 