The three sheaves of wheat are part of the arms of Cheshire. The horn may be the Wirral horn.
The Wirral Horn is an important emblem of Wirral borough’s history. The 900-year-old Horn was given to Alan Sylvester, the first Forester of Wirral, in about the year 1130. Wirral was declared a ‘Forest’ – land designated for hunting – in about 1130 and remained so for the next 200 years. The Horn of Wirral, indicated tenure by cornage, of the Master-Forester, a form of feudal tenure which required the tenant to blow a horn giving notice of raids by the enemy.
The motto means "Without the Lord, all is in vain"
The two words in the book at the bottom mean "Let there be light"
I can't make any suggestions about the shields. If you really want to know, I'd ask the school secretary.