Despite what Haynes etc. advise there is NO NEED to remove the timing covers or crankshaft pulley to change the waterpump on an Acclaim. All you need to do is remove the one bolt that passes through the timing cover and waterpump along with all the other waterpump fixing bolts, then simply loosen the other timing cover bolts by a couple of turns. You'll then find it's quite easy to wangle the old pump out and, with a little care, the new one in. I've done a few like this and it's not a bad job, really - couple of hours tops once you know the ropes but if it's your first one allow an afternoon.
Still miss the Triomatic we had, lovely to drive even though it was a bit of a shed.