@AlbionBro Denhams used to sell "anything" but I think they have upped their game in recent years. Take a look at their website, they have a sale coming up - you can subscribe and receive links to their catalogues by email.
For brass household items, do not clean, leave that to the new owner if that is what they choose. Probably the same for most items I think, antiques do not need to be nice and shiny.
General tip - if you have 2 of anything, they are generally worth more than double the selling price of a single...
That's called business, they have overheads. Tesco don't sell you tins of beans and loaves of bread at their cost price do they?
I would suggest looking at Sold prices on eBay particularly for smaller items which can be posted and this will give you an indication if what you have is something...
Well before my time probably closer to 1992 for me, I was usually well on the way by the time we got in there.
My only memory of the place is that it had black and green Tennent's lager on tap down the far left hand end of the bar if I remember correctly.