Hello Digger! I run several Watercolour Demonstrations and Workshops around the South Lancashire, Wigan, Warrington and Manchester area, and I have found that Stratford & York brushes are both good to use and extemely cost effective. My current workhorse brush is a "Stratford & York Large Jet" brush, and is often the only brush I use for my classes, and this cost me £5.20 (Still in the SAA Catalogue at this price)!
Many of my students now use this brush also.
If I'm doing Acrylic Classes, I tend to use the DR System 3 Brushes, which are again very cost effective.
I hope this may be of some use to you, but if you want more information, then please come back to me.
RSC Wigan Warrington area