FO Friday - A(nother) hot water bottle cover

 Did you know you can make rib in crotchet? Me neither, but now I do:

Elise asked for a replacement hot water bottle cover, because she's worn through the bottom of the one I made her in 2014. 

I know I could have offered to repair it, but the chance to get some crocheting in was too great. I took the yarn I had unravelled and dyed and went looking for a pattern... And looking, and looking. In the end I made it up on the fly. 

I'm really pleased with how it came out. I'm considering writing up the pattern, but I only speak crotchet as a second language. What do you think?