The best option for temporary employment?

[CAD Designer]

Currently trying to get back into work, there are a number of opportunities through agencies and employers with the option of PAYE or through an umbrella company for which I'd have to apply for an account, having always been PAYE in the past.

From what I've read, going the umbrella company route has the advantage of allowance for daily travel so take home pay is higher.

If using an umbrella company, is the umbrella company legally required to request a copy of your passport sent to them by post as proof of identification?

When you leave temporary employment, if having worked through an umbrella company, I presume the umbrella company completes and returns your P45 to you?