For Yak and Extra owners, for several years there has been the North Weald Formation School which is staffed for the week by very experienced military and ex-military instructors. There is also a spin-off course for RV owners run by a regular PPrune poster.
I would also suggest Ultimate High as a good source of quality instruction. There is some overlap in terms of that instruction with the North Weald course.
Alternatively, the OP may already know some people from a suitable instructional background. Either way, it is
essential to get proper instruction before attempting formation flying.
Forward. Up. In. Always have an escape route.
