I made a bid on eBay & set a maximum limit of £10, but somehow or other (almost certainly my sausage fingers), it has come up on eBay as £1000.
I have contacted the seller and informed them but had no reply& I have been in touch with eBay & withdrawn the bid.
I have had no reply from either.
So, my question is, assuming I have no response from either, where do I stand legally?
All/any advice is welcome as this is making me sick with worry.

I would say that if the error is obvious (for example bidding £1000 on a Clash CD) then there is plenty of precedent and the buyer will perhaps be annoyed but understand. Remember the kid who bid on a real JCB thinking it was a toy? His dad didn’t have to buy it. You might get a negative review but I can’t see you’ll have to pay. Again, you’ve taken the initiative by contacting them so I would sit tight. This specifically mentions bidding in error as a cause for retracting your bid:
https://www.ebay.co.uk/help/buying/bidding/retracting-bid?id=4013#:~:text=If%20you've%20made%20a,your%20bid%20in%20certain%20circumstances.&text=Keep%20in%20mind%20that%20you,cancel%20your%20bid%20for%20you.
Does the listing still show your bid? If it doesn’t you’re fine, and you can put your £10 bid in.
Presumably, only a worry (and a hypothetical one at that, given what’s written above) if someone is so determined to outbid you that they’re prepared to bid large amounts for the CD (or whatever)?
Tell the bank that you get your credit card from and tell PayPal. If necessary you can remove that account from your Paypal account to stop it being debited.
I hope you’ve not bid on a Bros. CD?
Most of the rights on eBay rest with the buyer, as I found to my cost when I was a seller
You’ll be okay, but I would approach it slightly differently. Tell the seller that you bid on the item by mistake, as you already have it (I’ve genuinely done this several times). He’ll maybe grumble, but will almost definitely cancel your bid. If he refuses, go to eBay and tell them the truth. They will then sort it out for you. Telling the seller the truth would almost certainly see him cancelling the bid for you, as 99% of sellers are honest, but there remains the outside chance that he’ll ignore your emails and get a mate to bid you up. If this were to happen you’d still probably be okay, by showing eBay your attempts to have the mistake rectified, but it just gets a bit messy. But as Dai says, eBay almost always sides with the buyer, as I too have found to my cost (even though it was as clear a case of the buyer lying than it could possibly be).
All I can say is it is a good job you don’t live in the USA.A few years back I was over there on business when one of the Star Wars films had been released. A restaurant in Fort Lauderdale was doing a promo competition and the prize was a Toy Yoda. The woman who won the competition thought she was getting a Toyota. Sued them and they agreed a settlement in her favour.
Are you still showing on the bidding as the highest bidder – if not then it’s been cancelled, otherwise retract your bid
https://www.ebay.co.uk/help/buying/bidding/retracting-bid?id=4013&st=12&pos=1&query=Retracting%20a%20bid&intent=retracting
you normally get an email confirmation – do they have your current email address?