Given the importance he places on his name (Linden this, Linden that), it is something of a surprise that his name does not seem to be Charles Linden. A quick check indicates that the Linden companies have as director a Lyndon Charles Griffiths.
http://companycheck.co.uk/director/915042271
It gets more curous. Charles Linden on the origins of the Linden method. “The Linden Center was founded in the summer of 1996. Charles Linden had spent over 12 months, with a substantial group of research subjects and the assistance of a clinical psychologist and doctor, identifying what it was that all recovered anxiety sufferers had done to cause their recovery – the resultant findings formed the cornerstone of what was to become The Linden Method program.”
He indicated that because of his anxiety problems he was declared bankrupt. However, a bit more digging suggests that the timing does not correspond with what is said on the Linden Method website. I found this curious entry from 1999:
https://www.thegazette.co.uk/London/issue/55406/page/1940
GRIFFITHS, Lyndon Charles, Freelance Producer/Director, of 2
Shruberry Street, Kidderminster DY10 2QZ, lately residing at Court
Chambers, Wyre Court, Wyre Hill, Bewdley DY12 2JS, carrying on
buisness as L G V S (Lyndon Griffith Video Services) Court—
KIDDERMINSTER Date of Filing Petition—9th February 1999 No
of Matter—6 of 1999 Date of Bankruptcy Order—9th February 1999
Whether Debtor’s or Creditor’s Petition—Debtor’s Official Receiver—
1st Floor, Lady wood House, 45-46 Stephenson Street, Birmingham
B24UP

So he developed the Linden Method in 1996 but went bankrupt in 1999, which seems inconsistent. And why would someone who trades on a method featuring his name (and persona) use a pseudonym?