After making enquiries at the social services in Somerset regarding the Blue/Orange disabled car badge scheme and regarding the level of disability you need to acquire one.
Firstly after checking the social services department the guidelines have changed in order to apply.
Since April of 2000 the person applying must be receiving the higher rate of mobility component of the Disability living allowance or they are registered as blind under the National assistance act 1948.
Also they could receive the war pensioners mobility supplement an application can be made via an occupational therapist and also your doctor can play a big part in your application.

In Somerset the application must be sent to:
Sedgemoor Enterprise Resource Centre
Northgate
Bridgwater
TA6 3EU
Or telephone: 01278 455571

You must send with your application 2 passport size photographs signed on the back and a cheque for £2 made payable to Somerset County Council.
One of the questions one could ask is "What if I don't meet the automatic criteria, can I still apply". The answer is YES providing you meet the following requirements:
1. You hold a valid driving licence and have a severe disability in both arms and you are unable to turn by hand the steering wheel of a vehicle, even if that wheel is fitted with a turning knob.
2. You are 65 or over and you have a permanent and substantial disability which causes inability to walk or very considerable difficulty in walking.