CSA assessment of Umbrella expenses

[DirtyDog]

Were does he say he expects to carry on?

At the end of the day it's up to the OP to decide and if he does just one gig then packs it in to get his house in order ready for an investigation in case it happens.

Does expectation even come into it?

When you hand your notice in to an umbrella (or other employment), you cannot claim expenses for travel and subsistence from that point on (location is no longer temporary). If you have been paid expenses for a location which was presumed to be temporary but is nor permanent, should you not rectify that by declaring the expenses as a BIK on your tax return?