Without reading the whole thing - If the water pump is changed it normally means draining the whole system (the pump is usually at the bottom of the system somewhere, so removing it means removing the coolant).
In my experience its bad practice to drain any fluid and put it back in again. So no, I wouldnt have thought they would have put it back in again.
With regards to plugging it into a computer - have a look on ebay. I bought an ELM327 lead from ebay and it was able to "talk" to my diesel Mondeo. its an OBD2 cable so sould be able to talk to most vehicles. it was only about £15-20 so might be worth a punt for you rather than pay £90. it could pop up enough of a fault code that you can google it.
In my experience its bad practice to drain any fluid and put it back in again. So no, I wouldnt have thought they would have put it back in again.
With regards to plugging it into a computer - have a look on ebay. I bought an ELM327 lead from ebay and it was able to "talk" to my diesel Mondeo. its an OBD2 cable so sould be able to talk to most vehicles. it was only about £15-20 so might be worth a punt for you rather than pay £90. it could pop up enough of a fault code that you can google it.