The William III farthing would be from the 1695-1701 period. Although I doubt the tamper is that old. I'd guess the tamper was probably made in the 19th century. The coins are too worn to see the dates, which would be on the reverse below the figure of Britannia.
http://www.ebay.com/itm/William-III-Farthing-Pipe-Tamper-William-Halfpenny-j668-/351460016596?pt=LH_DefaultDomain_3&hash=item51d4a641d4
Interesting that it looks like all the sellers auctions are metal detecting finds. Here's an awesome Cnut Penny. You can see on the reverse it says EDRIC ONN LUNDN. Edric would be the moneyer's name at (onn) London.
http://www.ebay.com/itm/Fabulous-Anglo-Saxon-Silver-CNUT-Penny-e9940-/351460007991?pt=LH_DefaultDomain_3&hash=item51d4a62037
Here's another interesting ring/tamper he says is from the Georgian period (18th century).
http://www.ebay.com/itm/William-III-Farthing-Pipe-Tamper-William-Halfpenny-j668-/351460016596?pt=LH_DefaultDomain_3&hash=item51d4a641d4
http://www.ebay.com/itm/William-III-Farthing-Pipe-Tamper-William-Halfpenny-j668-/351460016596?pt=LH_DefaultDomain_3&hash=item51d4a641d4
Interesting that it looks like all the sellers auctions are metal detecting finds. Here's an awesome Cnut Penny. You can see on the reverse it says EDRIC ONN LUNDN. Edric would be the moneyer's name at (onn) London.
http://www.ebay.com/itm/Fabulous-Anglo-Saxon-Silver-CNUT-Penny-e9940-/351460007991?pt=LH_DefaultDomain_3&hash=item51d4a62037
Here's another interesting ring/tamper he says is from the Georgian period (18th century).
http://www.ebay.com/itm/William-III-Farthing-Pipe-Tamper-William-Halfpenny-j668-/351460016596?pt=LH_DefaultDomain_3&hash=item51d4a641d4