Do not use Parasol as they are thieves who stole £800 from me. Do not use JSA because they forget to pay you. Do not use Giant because god knows how they work, but they pay you with "bonuses" and offer investigation insurance, which sounds all to dodgy.
I haven't yet used Orange and Gold.
Try contractoruk.com
I used nasa consulting for almost 2 years, they charge £10 a week which includes all fees and their phone support is fast and helpful.
I highly recommend them.
http://www.nasaconsulting.com/
Same day payment as well.
You can claim 40p/mile for the first 10,000 miles if you drive to and from your place of work as well which worked out really good for me as I had quite a bit of extra cash each week
why not get a limited company and you're the director rather then umbrella?
i did the maths for me and i get quite a bit more doing it through my own Ltd. than umbrella
A lot of people have used Orange Genie (I think - might have got that totally wrong?) where I work, and they complain about them a lot but I haven't paid attention to why.