Parasol
http://www.parasolgroup.co.uk/
PCG
http://www.pcg.org.uk/cms/index.php
Umbrella Company Price Check
http://www.contractorumbrella.com/umbrella-price-check.html
The UK’s Top 10 Umbrella Companies
http://www.top10umbrella.com/top10.php
Impartial Reviews of the Best Umbrella Companies
http://www.contractorsview.co.uk
An off-shore umbrella company
http://www.amlimited.com/the-aml-solution/comparison-chart/