You'd be lying on the online form because you're not the owner and you have to enter in the house registration number and I'm not sure if you have to take a picture of the blue/book chanote I can't remember what I had to do.
Only the owners of a property are given a paper form TM30 to register guests by immigration.
I suggest that you look up the penalty for lying on a government form.
Go do your TM30 yourself at immigration. My immigration never asked for one.