Fruit bush ID and advice please

I inherited this bush on the plot I took over earlier in the year. No one on site knew what it was, everyone told me the fruit was delicious and now that I have some I have to agree. It is obviously a blackberry cross, but which one? Boysenberry? It is a rampant triffid and will need some severe pruning and I am wondering if it would be best to take it all down to ground level and retrain it or just try to tame it. All advice welcome.

Could be a Tayberry, Boysenberry or one of those crosses.  If it is anything like mine it fruits the same as raspberries so you should cut off the fruiting branches when they are finished and tie in this years growth, cutting out any branches to ground level that are crossing or growing in the wrong place.

The valuable bits are the new shoots that are now probably trying to escape from your plot. These should be tied on to wires so you will need a big framework as they are next years crop. Just retain those that you want. After fruiting has finished cut out all this years fruiting shoots at ground level plus and new shoots that you do not want.