MM used his keyboard to write :
Thanks. I've seen the short hose with integral isolation valve for
around £3.50 on eBay or Amazon, but my local DIY merchant may actually
have one on the shelf. I note your comments about scratching the paint
off, but do you not rate paint stripper? Or is it corrosive on copper?

No need for stipper, just scrape it with a blade then finish with wire
wool/ emery cloth or similar.