They are the one the tackle shop next to Tesco Express in Weymouth selling at 2.25, I know cos I bought some last Winter .
They vary between 3.0g, 3.5g and 4.0g (only a few 4.0g), I think the 4.0g sells at 2.50-2.95, these have 2 extra spike on the back.
I suggest anyone want one, get a couple as spare, I used one last Oct and didn't wash it afterward, the small swivel at the top corroded.
When I used it on Pat Carlin's boat, he told us to rig it up as flowing trace (or Portland rig whichever) just retrieve then drop, retrieve then drop,.......
However, I spoke to the local anglers here, they just tie it to the line and jig it up and down like a pirk, but they do fish shallower water here.
PS, the fat bloke isn't me.