As well training with Heather Ashley we also run regular training clinics with Emily Harris (Dressage), Roland Tong (Dressage) & Cheryl Bezants (Jumping). We use all three trainers ourselves & find them all hugely beneficial. Emily & Cheryls clinics are open to all whatever level you are working at. Rolands you will find more beneficial if you are a bit more experienced.
See their individual clinics pages for more details.