The Disability Discrimination Act 1995 (DDA) replaced the quota scheme, the designated employment scheme, and registration as a disabled person under the Disabled Persons (Employment) Act 1944.
Now you don’t register as disabled in order to get rights under the DDA or Equality Act 2010; you just look at whether you meet the Equality Act definition of ‘disability’.
There are some transitional provisions though, which apply even if a person does not meet the Equality Act definition of ‘disability’. People registered as disabled under the 1944 Act both on January 15th 1995 and December 2nd 1996 are treated as having had a disability under the past.
These transitional provisions were contained in DDA Schedule 1 para 7. The 2011 guidance at para A17 says that the transitional provisions have been saved so that they still apply for the purposes of the Equality Act 2010 (this is probably under reg 16(1) of SI 2010/2317 (link to legislation.gov.uk)).