When he had saved up £10 he left the farm where he was working and bought an old pony and cart. He sold produce on Spilsby and Alford markets; in the winter he killed pigs for farmers. He earned one shilling for killing the pig and an extra sixpence if he cut it up as well. At this time he started an egg packing business with a friend.

He married Mary Jane in Welton le Marsh Methodist Chapel and went to live in Hogsthorpe. He took over a carriers business that included carting stone and coal. He bought his first cow for £16 and started selling mild for one and half pence delivered.

At the beginning of the First World War, the army took over his stables. So Mr. And Mrs. Dennett moved to Hundleby in 1914 where they worked hard to develop their dairy business. A fire burned down many of Dennett's farm buildings so they started all over again.

Mr. Dennett was the first to introduce British Friesian cattle into the Spilsby area which brought a lot of opposition from the owners of Lincoln Reds. His stock produced over five gallons of milk a day. He crossed a Friesian bull with red cattle rearing one cow that produced over 10 gallons of milk per day.

He opened a Creamery on Spilsby High Street and for a long time kept the egg packing and dairy business in Queen Street. He handed over the Hundleby farm to his eldest son, George and started to develop the ice cream making with his other son, Eric.

Arthur Dennett was involved in Methodism for most of his life being local preacher and holding offices of circuit steward society steward.