Hi
Before it closed in the 1970s, Bath Market was in Walcot Street, just north of the present-day Hilton Hotel. The site is now mainly a car park, although the Cornmarket building survives. I don't know if it was on the same site in 1830, but it was certainly there by 1855 when the Cornmarket was built.
There was also the covered market next to the Guildhall, which is still in existence.
Pictures of both here:
http://www.bathintime.co.uk/search/keywords/MarketIt is very unusual to give an address like Bath Market as the birthplace in the census, usually it's just a town or parish. I would think it could well be a mistake, although perhaps his mother delivered very suddenly while at work or shopping!
This seems to be his baptism, showing his family lived at Milk Street at the time (very close to Avon Street).
http://www.freereg.org.uk/cgi/SearchResults.pl?RecordType=Baptisms&RecordID=6729475They were there when his sister Charlotte was baptised two years earlier, and brother Matthew two years later.
http://www.freereg.org.uk/cgi/SearchResults.pl?RecordType=Baptisms&RecordID=6754098http://www.freereg.org.uk/cgi/SearchResults.pl?RecordType=Baptisms&RecordID=6731169(There is a bug in FreeREG which causes it to drop the numbers in addresses. For Charlotte they were at No. 27 Milk Street, Daniel No. 17, Matthew 27.)
David