A British 1848 Sixpence, uncirculated and in absolute mint condition could fetch up to £775 GBP. If it has been circulated but still in good condition, it might fetch anything from £30 to £325 GBP.
A British 1848/6 or 7 Sixpence, uncirculated and in absolute mint condition could fetch up to £825 GBP. If it has been circulated but still in good condition, it might fetch anything from £40 to £375 GBP.
A reputable coin dealer will be able to give a more accurate valuation.
NOTE - The reverse of these coins is upside down to the obverse. This is normal.
The Sixpence was not introduced into the currency until about 1550.
Probably nothing. Modified coins have no collector value.
The British Threepence was first issued around 1550 and last issued in 1967. The British Sixpence was first issued around 1550 and last issued in 1967. The British Florin (Two Shillings) was first issued in 1848 and last issued in 1967. The British Halfcrown (Two Shillings and Sixpence) was first issued around 1526 and last issued in 1967.
A Sixpence was a small predecimal British coin. Half a Sixpence was a Threepence, an even smaller predecimal British coin.
There was no British Crown minted from 1848 to 1886 inclusive.
All British 1935 Sixpences were minted at the Royal Mint London. There are no "D" Sixpences.
A British 1700 Sixpence, circulated but still in good condition, might fetch anything up to £1,350 GBP. A reputable coin dealer will be able to give a more accurate valuation.
The British Sixpence was known as a "Tanner". The Australian Sixpence was known as a "Zack".
A Halfcrown is the eqivalent of Two Shillings and Sixpence. A Crown was Five Shillings.
The Royal Mint did not produce any Sixpences from 1752 to 1756 inclusive.
The first British Florins were minted in 1848 as a tentative step towards decimalisation.
Good luck if you have one, but the last British Sixpence was minted in 1967.