Is it better here in switzerland or better I exchange in the UK?
And if it's here so bank/exchange shop?

Errrrmmmmm iirc the max limit you can walk in and exchange in the UK is £2500 so I wouldn't be going anywhere with 10k chf I think you'd be talking t the BIB pretty quickly trying to explain where you got it and whats its for.

Better off doing it bank to bank

Casino

I can't do it bank to bank from here because I don't have a swiss account.
Best exchange place in swiss someone?

you have a bank where you are? ask them

on that amount of cash you'll be setting alarm bells off, and any walk in place will give you a shit exchange rate

I can do it for you - and give you a better rate than a bank ....... I just have to think of the best dark alley place, to meet you in.

with someone like me who is selling GBP and buying CHF?

hehehehe this has bad news written all over it lol

For a good FX-rate, you should find someone who has a CHF-account in Switzerland. The person transfers the amount to currencyfair.com for you, from there you can transfer it to your GBP account, then withdraw cash from there.
.
Actually it might be possible to pay the money into currencyfair at the counter of any bank (against (limited) fees?). I guess, without other options, that´s the first I´d try to establish with currencyfair customer support.
.
There are no good rates for cash <--> cash exchanges, except if you happen to find someone who needs to change the other way and you mutually agree to use the median rate between yee.

Bank : Please can you tell us where you got this money?

EF Guy : Some bloke from the internet. I'm sending it to Israel for him.

Bank : Sure beans. That'll be fine.

Didn't the OP ask?

Yeah, but
And I know they'd likely be transferring to UK, rather than Israel, but it'd not make much difference and Israel made for a better story (what with the OP being from Tel Aviv and all). I was going to write "Middle East", but thought that was maybe a step too far.

So we are not talking about you laundering money made on your dodgy market stall then.

It's for sure here...

I'll give you £5k cash!

All you need is a "Credible Explanation". I asked a bank not long ago and that is what they told me. If it is dodgy keep off the internet.

Are we starting an auction? £5100!

Most self-respecting Swiss people wouldn't leave the house without at least CHF10,000 cash in their wallet, so I don't think that a bank is going to ask too many questions.

For 10k ?? They wouldn't even bat an eyelid let alone ask anything.