UK - Criminal Background Check

In the UK a ‘Basic Disclosure’ will be sufficient when applying for an E-2 Visa.  
You can receive your basic disclosure through the following company; Disclosure Scotland.

Please also telephone Disclosure Scotland and request that the Basic Disclosure is Notarized before returning to you as you need to submit it to the Foreign Office.

In the UK a document must be notarized before it can have an Apostille stamp applied.

Link: http://www.disclosurescotland.co.uk/