Going to the ASA is the first port of call, although it sounds lilke this is an 'internal' arrangement and not, strictly speaking, an 'advertised' product.
More importantly, I feel, is to check with the CAA that they have given this transfer of training to another provider their blessing. I say this only because the management of the new company, having no connection with the old (?), surely must be liable for fiduciary exchange and the terms thereafter maintained should reflect this.
Of course, this could then justify their alleged £15000 administration fee.