As for WW1 scenarios involving big guns on table, something around Operation Michael is your best bet. There are two options. One is for the opening day of the battle - March 21st 1918. The morning was foggy when the German attack started. The artillery bombardment was specifically targeted at, amongst other things, the various command and control centres on the British side. Some of the siege and garrison artillery batteries found themselves out of touch. The spread out nature of the British defence, the fog, and the bombardment all combined to enable German infantry to penetrate through the forward defensive lines in some places. The first that some gunners knew there was a problem was when, as the fog lifted, they came under MG08/15 and rifle fire from German infantry. By this stage there were British units falling back in disarray in some areas. The stage was set, therefore, for a scenario where a determined artillery officer has organised his men to use their rifles and Lewis guns (issued as anti-aircraft and anti-personnel defensive weapons to artillery batteries) to ward off such an attack. The officer will have rallied some British stragglers to help.
The second scenario would have occurred during the retreat in the subsequent days. In many places the heavy guns were packed up early in the fighting and withdrawn ahead of the rest of Fifth Army. This scenario would involve a heavy artillery team that pulled out later and then had the misfortune of the gun slipping off the road and into a ditch. While attempting to get things moving again, the German advance guards crest the nearby the hill. Once again, British infantry stragglers are pulled into the fight.
Both examples are based on actual events.
Robert