Raspberries and weed membrane

Bear in mind that each plant will eventually form quite a wide clump, and that you need access for picking - staggering the planting in the rows would help with the spacing and with access from each side, but one foot between rows still sounds too tight to me.

If they didn't produce such delicious fruit they would probably be regarded as garden "thugs" - they will sucker both near and far from where originally planted and I suspect that weed fabric not only wouldn't stop that but might encourage them to shoot up further away (i.e. exactly where you don't want them to!)

Mulching is a more rasp-friendly way of covering the bare earth between plants and will make it easier to spot and remove unwanted suckers.

There's not many nicer weeds, though! 

I have two rows running east to west, one row autumn (south side), one row summer (north side). They are in a 5ft wide bed, with about 2ft between rows, the've done really well. But have thrown up LOTS of new canes upto 3ft away from the main plants (mainly in the grass pathways). But so far its worked for me!

I think the only reason the RHS states 6ft, is to allow access between the rows. I can access mine from both sides and tie them into wires. But there is still a bit of digging out of new canes to do. But give them to fellow plot holders and aid raspberries in their efforts for world domination!