Thank you everyone for your supportive replies. I'm so used to their behaviour that it's hard to tell what's U and what's not!
@Nightmanagerfan yes, they're usually worse than this. I hoped my illness might improve things, though to be fair the fatigue has crept up since last time they saw me, so they may not be fully aware of it.
@MyBrilliantDisguise yes, I didn't realise how many, and how good until now! Some school gate mums especially have proved themselves to be priceless.
@tigerdog thank you. I hope you're doing well now? 
@KimmySchmidt1*@Sparkletastic @BewareOfDragons* @Flicketyflack good idea about using DH as a go between, thank you. He's pretty non confrontational, and usually just rolls his eyes when they behave like this, but I just can't be arsed with their nonsense now. They have both offered to help, but are less good about following through with anything I suggest. My sister has been a lifesaver.
@Glumglowworm @BackforGood you're right. It's time to be strict and selfish. I usually get so much grief for doing anything remotely like that, but am now too tired to care. I like your approach @TwitterQueen1, hope your treatment has been successful? 
Thanks @aaaaargghhhhelpme they usually do a very good job of making me feel like the self absorbed one, which is why I'm not sure if it's them or me!
Thanks @Stopyourhavering sounds like you've been through it? Hope all is OK now.
I'll start chemo right after radiotherapy ends, so the fatigue will be around for a while. They will have to get used to it.
Thank you @Santawontbelong, @TheHodgeoftheHedge @pallisers @chitofftheshovel and @Floralnomad 