I think there's several solutions. I have
P -> S -> V -> R -> H -> L
From the clues:
- At least one of the vehicles is serviced later in the week than the hatchback.
This just means that H cannot have the last space
- The roadster is serviced later in the week than the van and earlier in the week than the hatchback.
This means that H, R, and V must be placed in the order V -> R -> H (with maybe something in between each). Also, from this and the above it follows that neither H, R or V can take the last space. Neither R or V can take the second to last, and V cannot take the third to last.
- Either the pickup and the van are serviced on consecutive days, or the pickup and the sedan are serviced on consecutive days, but not both.
This means taht P must be besides S or V, but not both. That is, the sequences V -> P -> S and V -> P -> S cannot exist, but P -> S -> V and V -> S -> P are fine.
- The sedan is serviced earlier in the week than the pickup or earlier in the week than the limousine, but not both.
This means that we need either P -> S -> L or L -> S -> P (with something in between)
My solution is jsut the first think I tried that fulfilled the above.