Hi,

We have a friend who needs oxygen to get about, but she has only been
supplied with the big bottles, which are not portable.

As she has not been able to get a portable one, I bought one for her
from a scuba diving source. The guy who supplied it said that we can
just go to a chemist and get an exchange when it is empty - does anyone
know how this works. E.g. do you have to register, or pre-book, or do
you just go in, hand over the old one, and pay the money?

I dont think she has long to live, so we want to get this sorted
quickly.

Many thanks