Hi Beth.
First I'll introduce myself as an amateur plumber.
My own view is cut into pipe kits should be banned or have big warning. You have one reason. Also in time I guess they could well leak.
I'm guessing this is under the sink also where your incoming mains comes in. Can you include a photo? This is a critical area, and if you can I'd use a professional plumber to sort it out, unless you enjoy plumbing.
If you have a drop in stainless sink and drainer, it may be easiest to take that out to do the work, but have to be careful not to damage clips and seals, also carefully reinstall ( most professionals therefore will be skilled enough to leave the sink on and to e.g. lie on the floor and do the work blind one handed, but do a better job than rest of us in a fraction of the time).
Now if it's not leaking and you can live with slow loo then I'd leave for time being until Corvid-19 restrictions eased, although if you all take sensible precautions you prob can find a plumber at the mo who needs the work.
Best job would be soldered by a professional, otherwise use compression fittings. If pushfit used then need to add pipe support which may be time consuming and tricky but not impossible. A photo would help people comment on the best solution.
Please ask on any points where I'm not making sense.
Apologies if this sounds downbeat.
If you want to learn plumbing though, you now have water in the garden, so can get some bits (Inc reused scrap) and practice there first. As a very great chef said "practice, don't wing it". The same is true for plumbing. You need regular practice. That's why I'm here on this forum, to remind myself of stuff and keep learning more. It's also time I did some plumbing.
Cheers,
Roy
