Unlike a number of other German states, the Frei Stadt contracted out a 2 battalions of line infantry and a battalion of light infantry to the French. The troops marched in easy stages to Cherbourg where they boarded ship. They assumed their destination was America, but 2 days into the voyage the sealed orders were opened and the force headed towards the Lancashire coast of England.
Arriving unseen off the coast the fleet anchored and seized the small port of Glasson Dock. This enabled the infantry and some light gins to land, but to unload the cavalry, heavier guns and supplies a major port had to be seized so the force set off to capture Lancaster.
The reality was that the British had spotted the fleets change of direction and an outward bound convoy of Brunswick infantry was diverted into Lancaster to reinforce the local British troops, just in time.
The French forces consisted of 2 battalions of foot, 1 battalion of grenadiers, 2 battalions of Frunsberg line and a battalion of Frunsberg lights and 1 battery of light guns
The British force had 2 battalions of foot, 1 battalion of Grenadiers, plus 2 battalions of Brunswick line and a battalion of Brunswick lights and 1 battery of light guns.
Deciding that the direct back road from Glasson to Lancaster would be blocked and that the main road from the South would be as well the French took a little back road across to Galgate and then to the east of the main road hoping to outflank the British position and storm Lancaster before they could respond.
The British also had a cunning plan, they decided that the direct back road was to obvious so they positioned themselves on the high ground to the east of the main road at Bailrigg intending to hit the French in flank as they passed.
Approaching Bailrigg by the back lane the French were surprised to find British troops already in position, but being partly on the Britsh flank they pressed on feeding their troops into the growing combat as they arrived.
By dusk both sides had fought themselves to a standstill and the French and Frunsberg forces deciding they could only face growing resistance withdrew to Glasson Dock and re-embarked on their ships.
This was fought in one evening at the Lancaster University Wargames club in 1974 roughly on the same position as the fictional battle. I was the umpire and up until the battle both sides movements were on maps.