Changing credit cards - advice re existing card credit limit and balance transfer

JM5410

I have one credit card which the current 0% purchases deal runs out 1st March 2021. I have a relatively high limit of £13000 (which I've never gone anywhere using). I currently owe about £3000 on it which I had intended to pay off by March.
So a few questions:
1 - will a new credit card company consider I have a high credit limit already so won't give me further credit? Or is so itll be alot smaller? I intend to cancel my current card once I get a new one.
2 - should I reduce my current credit card limit to help with 1 above?
3 - if I leave some of the money I still owe on the current card and then ask for a balance transfer, does that improve my chances of getting a new card or are balance transfer requests irrelevant?
Thanks in anticipation.

[Deleted User]

Keep your card as it is. Lowering the limit of your only card will make you look higher risk.

Also keep the card once you have your second.

If you don't need a BT, then clear the debt. Carrying a debt lessens your chance of further credit.

I'm assuming you mean your current deal runs in March 2022, rather than having already run out.