EFRBS - Sole Trader

A client with a sizable tax bill who doesn't want to become a LTD has spoken to another acocuntant in a pub (don't you love that?!!) who apparantly has advised him that using an EFRBS was the way to go to mitigate his bill.

Now I don't really know anything about EFRBS and need some quick comments while I'm researching!

Presumably it would only be relevant if he were a company so the contributions could be deducted form the tax bill? Do the contributions still work the same as increasing his tax band?? A bit confused!