In the junior competition, Arahan Pilkington came third in cornet, Bryn Morgan and Toby Clark got silver in duet, and Bryn Morgan, Luke Squire, Reagan Carver and Clark came second in junior ensemble A.
Clark also came third in junior horn and first in the junior baritone.
Mitchell Cosford took home silver in Under-15 cornet.
In the Under-15 Other category, Bryn Morgan picked up first place, followed by Concert Brass members Arne Leiva-Benegas in second and Moata Leiva-Benegas in third.
Jellyman said the ongoing Covid-19 pandemic had impacted this year's competition with one section of the band competition, the street march, not going ahead.
"We were short five players but the band fraternity is such an amazing thing that everybody looks after everybody," he said.
"A few friends helped out and we managed to get the thing over the line."
After "settling down a bit", the band would analyse the judge's report and look for any shortfalls, Jellyman said.
"When you sit and listen to a whole bunch of bands in a row, who to all intents and purposes have the same instrumentation, it's amazing how different they sound.
"We are after a particular sound and we think we're really close to it.
"Playing A Grade means we have to keep working away on technical things."
Jellyman said it was the best team he had ever worked with, with the entire band working hard to achieve its goals.