FreddieSwan:
They’ll normally be honest, but simply ask - what do each of them charge?The ‘better’ ones likely have a flat fee based on an earning up to £x and a higher flat fee for above £x. Those that scale with percentages will just mean the more you earn, the more you lose. If you’re paying ~£15 a week flat fee for an umbrella service, you’re probably earning a decent enough living and your overtime won’t be affected.
Also, do they have an expenses system set up? And how is your holiday managed?
The umbrella we use atm pay holiday upfront, so opposed to it accumulating in an umbrella ‘pot’, it’s paid upfront every week. Just means when you’re taking holiday, you’re taking time off and should have budgeted for it from your earnings rather than being paid whilst you’re off. In terms of expenses, they have a really simple spreadsheet not dissimilar to a timesheet, so really easy to work with.
Unfortunately it’s none of the above and I’ve never dealt with them either!
So, there’s no holiday pay.
If you work, say 13 weeks @ £500pw, leave, do 13 weeks for any amount somewhere else, and await your holiday pay from the previous agency - you don’t get £500 for your week off - when PAYE employees are entitled to a week’s holiday accretion every 13 weeks - and that’s WITH that week’s holiday paid at the average week’s wages to boot!
Attempting to palm off the downside of Self-Employed and wrap it up as “Pseudo PAYE” where you get both a sub-standard hourly rate for self-employed, but still have all the paperwork overheads is one of the many aspects of “Umbrella” which I consider to be a fiddle.
50 hours @ £10ph pays better at the proper PAYE agency than 50 x £10ph does at the Umbrella outfit, BECAUSE they’ve charged £27 or whatever which you barely make back from the accountants “putting in for tax rebates early” - ie the backwash make-up money comes from HMRC rather than just being paid a proper wage with full holiday entitlement to begin with.
It’s a total scandal that any self-employed contractor should get less than £15ph in this day and age. £10-£14ph will do for PAYE, but NOT for a job that accrues no holiday entitlement without a deduction from one’s pay - £1ph does NOT cut it there. About £4.50ph would be accurate, but I’ve not heard of ANY agencies paying this amount over for “going on the umbrella”, thus I conclude that the fiddle is still alive and well, and more importantly - still being pushed! 
