We are mostly into growing plants so probably nobody on here will be qualified to give you an estimate. I would try asking your local museum. An antique dealer might help, but could be influenced by the hope that you'll sell it to him to make a profit on... You might also get advice on whether it would be a good thing to clean and paint it or whether that would detract from its value. There'll be somebody out there that will love it anyway!

Hard to say - in terms of practicality, I doubt its meant to hold a plant, for one thing, its too small for any decent sized pot, and the wicker work top would rot through fairly quickly. If its not antique, its probably just meant to be an ornament, either in the garden or indoors.

I would suggest that this may be Victorian, either a childs toy or a sales reps model to demonstrate to prospective customers. If you have an auction house that has antique sales near to you I would ask them for an opinion. It is not really a charity shop item, I don't think.

Most charity shops have an antiques dealer visiting their shop regularly ... surprised if yours doesn't! As Stera suggests, take it to your nearest museum for some information. Good luck!

Found one just like it up for bid on eBay so far $649 US dollars.