Kids air boot (Parkside SK7)

Hi, this may seem like a strange request however I'm going to ask anyway. My daughter would like to prank her school on April Fools Day and as such would like to pretend she's broken her leg and we already have some crutches so we just need an air boot so she can pop it on in the morning and then pop it off and start running around at break time so everybody be like oh my God. This may seem very odd, but we are actually quite an odd family. If anyone in the Stockport area has an air boot that a child no longer requires or that will be out of an air boot before the 1st of April please let me know and I will quickly come and collect it because this will be quite a funny prank, it doesn't matter which leg either will be fine.