hello john i picked up this very nice watercolour scene today
its unsigned to what i can see but it may have a signature underneith the border, i dont know

i think its excellent quality and looks like some kind of venetian scene

what do you think in terms of value for an unsigned work of this quality?

Looks nice.
I would not think it is antique.
Hope it cost you under £10

do not like the frame a bit too 1970s

Find an older frame and swop them around, may look worth nearer £50 / £60 then

good luck