Radiator issue

A stuck closed thermostat would cause a cold bottom radiator hose due to no coolant flow. But you'd also see an overheating problem, so I'd rule that out based on what you've said about all the other hoses heating up as they should and the temp gauge reading good. A failed thermostat will give obvious signs when it's gone.

When did you feel the bottom hose? It may be that there's nothing wrong and the car wasn't driven enough for there to be enough of a heat buildup in the bottom hose. Take it out for a good hard spin, come back, let it cool for a bit, or even if you can safely get your hand on the lower hose while the engine is still hot, feel it again

That would definitely be enough, should be feeling the temperature change from cold to lukewarm on the bottom hose once the thermostat opens up.

If you want to check your thermostat is stuck open, start the car from cold and then open the radiator filler cap and look at the coolant to check if it's flowing, if it is flowing then the thermostat is stuck open. Leave everything as it is, wait for the car to come up to operating temp, then look through the filler neck again, if there's flow now it means your thermostat is working, if there wasn't any flow when car is warmed up then the thermostat would be stuck closed.

The radiator could be clogged, but I don't think so, pretty much everything that would cause a cold bottom rad hose will also cause overheating.

Local Car Mechanic could be right, it could be that the cooling system is just running very well after the water pump fresh coolant.

It doesn't seem to be doing damage if you drove from the nations capital to what the people who live there think should be the nations capital ;)

Bring it back to the lads who did the water pump and see what they think

Radiators are grossly oversized for normal driving but are sized really to stop the cooling fan(s) running continuously while idling. I have watched the temperature on VCDS while driving and it varies only a few degrees at most and generally stays around 87/90C on a few of the family VWs which is indicative of a very clean system as the thermostat is only opened very slightly. In the good old days when coolant gauges actually meant something, the "needle" would only move a few degrees under all normal driving conditions and would then rise while idling for prolonged periods until the cooling fan cut in. The modern ones are basically pretty useless as most are now like the VW/Vag group of cars? (certainly since 2000) where the gauge indicates the true reading up to ~ 75C, it will then move pretty rapidly to indicate a rock steady 90C between 75C and 107C so no indication whatsoever of impending trouble but how many people now days actually look at their gauges or wondered why the cooling fan keeps cutting in/out at a indicated 90C.

A bit ironical really I suppose but there was a "fail safe" (fail open) thermostat in the famous VW Beetle, the cooling flaps were spring loaded to be fully open and the linkage was attached to a copper corrugated "canister" which was partially vacuum filled and was anchored to a bracket, in the cold condition, the stat was reduced to its minimum length so the flaps were closed and only allowed a very small air flow over the stat, as the engine heated up the air got hotter and hotter and the corrugated canister (stat) started to expand and so gave the required engine cooling. The system could only fail in two ways, either the linkage broke or the canister was holed and lost its vacuum, resulting in fully open flaps and full cooling but no engine seizures. Fail Safe??, of course the flaps could jam closed but they were a pretty loose fit so unlikely. I think I saw a 1950s (water cooled) Riley that had I think a corrugated thermostat or stats which presumably achieved the same result.

VW Bora (Jan.2000) 1.4 AHW (petrol)

Thermostat begins opening at 86C. Fully Open at 98C.

Fan Speed 1 ON at 92C to 97C.   OFF at 91 to 84C.

Fan Speed 2 ON at 99C to 105C. OFF at 98 to 91C.