It seems thirsty -- how often are you watering?

I see about the mix, that's in the UK, right?

What light/sun exposure does it get? All of these factors matters in this.

is the mix hard to the touch?

If I were using John Innes #2 for this plant, I would cut it deeply with about 8 parts pumice and definitely skip the moss. It thrives with frequent drenching in a very fast-draining mix that retains little water (frequent means weekly-ish. I tend to dry out mine). You have to adjust your substrate so you can do that without having it sit in wet substrate too long.

Pagan

It's right near my door so gets good light, yes maybe where I'm going wrong, as its classed as a succulent I thought I might overwater it. The mix does dry out very fast! Be ok to repot now? Not sure if we get pumice here in the uk? Is perlite ok? Soil, perlite and bark?

But pls, wait, it's GOOD that the mix dries out fast.

Pls. answer FIRST, is the mix hard to the touch? It's important to determine WHY /HOW it can be that the plant isn't drinking (other than maybe to pot's too deep).

If not, I'm unclear why you'd repot other than to remove all moss.

Also, that pot looks rather deep (unless it's a distortion of the photo). Additionally, I find mine do better in plastic pots than clay, think it helps it conserve a BIT of moisture.

Perlite would do fine in lieu of pumice (most here say pls. sift it first to remove the powder/dust). Not sure abt the bark, maybe a 1/3 each to start?

When was the last time you gave it a drink? How much water?

I find this plant to be extremely tolerant of considerable dryness :-) I might water mine once a month or so (approx. same size pot as the OP's) but I do water very thoroughly when I do.......generally by placing the pot in the kitchen sink where the long 'vines' can drape over the edge and dowsing it fully with water. And then I ignore it for weeks!! Mature plants will develop water storage tubers at the roots and often along the stems that will help it survive an extended period without irrigation. And mine gets a lot of light, hanging in a west facing window. The 'vines' are very long - more than 4' - and it seems very happy and flowers periodically so it must like this approach :-)

I am not familiar with your soil mix but a fast draining mix like the 5-1-1 or a better cactus mix would be appropriate.

It's not hard to touch noo, and drains through very fast. Maybe I'm not giving it enough water when I do so? I maybe put in say half a normal can of coke ammount, (water of course not coke ) .

Water thoroughly until the water runs freely out the bottom - you may need to do this at the sink (where I water all my houseplants in a similar manner) and then let it dry almost completely before watering again. I will sometimes let the plant pot sit in a bowl of water of water for a short time, just so all the potting soil gets fully saturated and those water storage tubers completely rehydrated. Again, this is for a plant that is currently potted in a very fast draining soil medium.

Thx for answering that the rootball is NOT hard, but still, I don't see an answer for why it's NOT drinking.

Again, when was the LAST TIME YOU WATERED?

1/2 a can of coke would be approx 6 oz. assuming a 12 oz. can. There's no size reference to the plant's pot other than yr fingers. That suggests a smallish pot -- pls. measure for us across the top (like its diameter) & then also its height or depth. I'd vote for a more shallow pot, like a 3" pot.

Will try to share pix of my plant from home tonight.

Not sure I have a pic of the pot. This is a different leaf than yours, but it's still ceropegia woodii.

Here's its wacky bloom for those who have never seen it. It surprised me w/ 1st time bloom this past mid-October.

Night shots just to show normally hydrated leaves.

This is in a 3" plastic pot suspended above a pebble tray which pebbles you can see in the lower left. This way I can water to overflow & it flows into the pebble tray where the overflow can be evaporated into the plant at its leisure.

Hey. How's your plant doing?