I found this jacket on Amazon for £9.99.
It ticks all the boxes for me & Penny looks adorable in it.
Available in pink or blue & comes in a range of sizes.
It’s waterproof & keeps the undercarriage & back dry. It has a cute little hood with drawstring, and a handy little zip pocket for poop bags or treats! Velcro fastening makes it easy to put on/take off. Super stylish!
Frencie Mini Couture Waterproof Dog Raincoat - Pink (medium) https://www.amazon.co.uk/dp/B00W2S8QIG/ref=cm_sw_r_cp_api_glt_fabc_FXCN5WK9GGBCEA67152K?_encoding=UTF8&psc=1