I'm guessing that on your 16v, if that's all you've done, you may have put the plugs leads back in the wrong order (unlikely with a 16v)........or, sometimes if you have a bit of an oil leak into the plug wells it can smeg up the leads as well as the plugs?
Dad's......8v or 16v? sounds like the starter could be knackered but given the work just done he may have forgotten to connect back the earth strap to the gearbox so not enough current is getting to the starter....this is a common error, unfortunately if it is an 8v the tendancy is for the earthing to go through the ecu and fry it!! The injectors then stay open and fill the cylinders completely with fuel so the starter can't turn the engine over. Check the earth strap is connected, if it is connected then try the following, if it was not connected do not!! Jump the starter straight off the battery +ve to the smaller spade terminal, you should get a click at least like you were getting before, it might turn over. If no luck, jump to the larger terminal with the nut, the motor should spin fast but not engage the flywheel. If it does not spin then it is duff, if it spins then the solenoid part of the unit is probably duff. If the earth was not connected then come back.
