How is tax paid?

[JadeH94]

I am a UK citizen and resident and I have recently received money to the sum of $560,000. This money was obtained in the US and is being counted as income. It is currently held in an online account with BarclaysX but I wish to transfer it to my Royal Bank of Scotland account here in the UK. BarclaysX are claiming I must pay 35% on it, which is fine, but they are saying the 35% will come off before it is transferred to my RBS account. Is this how it works? Does it not get transferred in its entirety of $560,000 to my RBS account and then I pay the tax?

I am concerned they are trying to scam me out of 35% money. 

[Critter-3]

Where did this sum come from ?   Was this an inherited IRA ?