Maybe he was already into drug smuggling, giving him reason to not tell the full story about the theft and/or why he had all his money in cash.

He was already familiar with shipping rules, had a friend who casually threw together an interesting crate to smuggle himself in, etc.

While I don't know enough about banking back then, I presume there was a system in place to withdraw money away from your home bank, albeit it was likely slow. I'm guessing his issue wasn't necessarily that he didn't have money on him.

This worked for centuries:

https://en.wikipedia.org/wiki/Traveller%27s_cheque

I was meant more with regard to keeping 'that much' on him in the first place than not being able to replace it.

That too of course, just not making assumptions of other means I suppose, and it was the 'life's savings' being carried about that stood out.

Maybe he was working cash in hand while in the UK.

Yes, I don't doubt it. Would you keep it all ('savings') in hand though, if that's how you were paid?

The money-in-a-mattress stereotype exists for a reason. Although in the past, their parents most likely told them some awful tales of banks becoming insolvent or screwing them, and maybe he didn't have good documentation to open an account?