Input VAT on purchases of assets prior to registration

Heli

Please can somebody advise. What are the rules surrounding claiming input vat on assets purchased prior to VAT registration.
How long can I go back and what is the lowest value of asset that can be claimed for (£2000)? Also is there a restriction on the type of asset?
Thankyou

KernowAccountant

http://www.hmrc.gov.uk/manuals/vitmanual/VIT32000.htm

Heli

Thank you