This almost the exact same method I eventually employed on the BA from about 1981-85, with huge success. After moving to Bath in 78 I discovered the BA was a somewhat different animal from the WA at Tewkesbury, and I had to relearn the art of angling all over again. I was 23.
Initially I was fishing with standard link leger, with corn, meat or lob worm. Then discovered the amazing power of hemp introduced into the swim. A successful day would have been three or four barbel, plus a few chub, prech, bream or roach.
Of course I read the Anglers Mail, and always went through the match results printed in the back of the paper and was pretty much gobsmacked at the weights of barbel and chub attained in matches on the Severn. Right, this swimfeeder method would have to be given a shot on the BA I thought. I gleamed much useful info from the ever wonderful and informed Steve Curtis at Fish And Shoot in Bath. A bonus of being a regular there was the coffee and great banter. In addition, I met the extremely affable Pons. Hello Pons if your in here!
So now I was equipped with knowledge, bait (3 pints of hemp, 3 pints of casters and half of red maggot) and the required tackle, so off I trotted to one of the hot spots, which was the weirpool at Lipmley Stoke. Fishing at the tail of the pool where it shallowed up to the gravels before the bridge I catapulted in a pint of casters and a pint of hemp. I set up my rod (nobody fished the rivers with two rods then), cast in and proceeded to bag up like I had never had done. The flood gates had opened.
If I caught less than four barbel (along with a wealth of other species) over the course of a day's fishing, I could almost call it a naff day. So to this day, I can say that given the right swim and population of fish in it, ie not stuffed with small silvers, it will out fish any other method I have since employed.
And as for cost. Personally I wouldn't say that spending £15 quid on bait (4 pints of casters and 4 of home cooked hemp, max) for a days excellent fishing isn't overly expensive. In fact I would say that's excellent value.
I employed the same method on the HA to limited effect and the D. Stour at Throop with great effect. But here on my local Gt. Ouse generally it just don't do the same damage, as the population of silvers is so much greater.
Apologies for going slightly off piste from the lead subject.