The specimen pool isnt all that big and you would be surprised that there were big fish in it.
If you are going to fish it then you will need to use a bigger bait, if you have some boilies then i suggest you wack a big handfull into a bucket of water and let them washout until sunday.
If you are going to use maggots on a match anglers hook then i suggest you take a walk around the main lake and fish the very near margins with a big hookfull of wrigglers. You might also try the other lake at the far end of the venue (cant remember name of it) but it has some lovely fish in it and isnt hammered as much as the main lake.
dont forget to buy a bacon sarnie in the cafe and give my love to Debbie if she comes round with the tickets.