If there's anything quite tight on it it can take a while, when I did the cambelt on my rex, it ended up taking just half an hour to undo the bolt on the crank pulley.
in saying that, its really only an hour to get S*** off, give yourself an hour to align, replace water pump etc, then another hour to put stuff back on/top up fluids, at most with complications maybe 4.5 hours, say of the cam pulley's are playing tough when you go to replace the seals. etc.
-though actually looking- that's a quote and they'll over-estimate so as to not charge you the extra 10% fee that you'll see noted down.
-also, go to mot, see if you can't get a quote from stevens auto if they aren't too busy this time of year. Not sure on the pricing-as I always did my own but they're a good bunch and should see you right.