You know, Geddy3, it is a nice idea for me here, in PA. We have a local bear Yuengling Lager 
I can leave it for my guests who is not from next door states.
Last night I had guests from DE, USA celebrating 3 years of marriage, I gave to them a bottle of wine from New Zealand.
Someone gave me chocolate from their country one time. Apart from that no other gifts except food left behind.
I am getting a lot of wine bottles. But my guests know that I am a wine specialist. I have a lot of wine in the area that I rent out as airbnb. it is the coldest place in my house, I just say to the guests that my wine is not for them
@Geddy3 - would you pm me your listing? We think we are coming to the UK next May/early June.
Any other UK hosts are welcome to do so - we are 5, though.
Don’t think 5 sharing one small room would be adequate at mine. 
Our listing is only for 4 but I sent you the link anyhow…
I know it’s too late to answer this for you, but for others in the same circumstance; one of my favorite cooking blogs, technicolorkitcheninenglish.blogspot.com, is generated by a Brazilian blogger. She is always posting about what ingredients are difficult to obtain and/or expensive in Brazil (poppy seeds, cake flour, sour cream, Granny Smith apples, maple syrup, etc.). I’m sure it would be appreciated, especially if you’re staying with people who like to cook, to ask beforehand what ingredients they are interested in from your locality.
@Marina, I would not suggest candles. However, here are some ideas: coloring books for adults with coloring pencils, anything Victoria Secret (i.e. body lotion),wine bottle opener, fancy salt grinder (with salt inside), etc. I’ve traveled a lot to Brazil and always bring gifts. Naturally, if there are children, gifts for the kids.
Miss Miami, thank you!
I already took candles to Brazil.
I would not get Victoria Secret things, for me it is junk. All those lotions smell not good for me.
And yes, when a host has children, it is so easy to give a present!
I’m dimly aware of the existence of the Cornish language, but do people actually speak it?. I’ve never been to Cornwall, and the entirety of my information about it is from Rosemary Manning’s Green Smoke and sequels, about the Cornish dragon who befrends a girl called Susan. But that might not be a accurate depiction of Cornwall.
Oh, and nice web page.