No. This years new growth is what next years raspberries will grow on, Dab, so just cut the tops off at about 5 to 6 feet to keep them under control.

Agree. Only cut out the old canes and leave the new growth because that's what will give you fruit next summer.

Don't leave too many new canes growing, as they can easily crowd each other out - I made this mistake last year. I should also have fed them with ferrous sulphate at some stage because the leaves became chlorosed - too much competition, apparently. The crop wasn't nearly as good as in past years.