By 1985, Stewart & Lloyds Plastics was becoming an increasingly dominant presence in the UK and was known as 'The Pipeline People' and 'Pioneers in Modern Plastics' thanks to its prominence in the trade press, its product literature and its fleet of lorries delivering product across Britain.
The company invested in new, large bore facilities to help it diversify and capture market share from steel pipe manufacturers. By the end of 1985, Stewart & Lloyds Plastics had the widest range available from a UK manufacturer. It produced the largest PE pipe yet manufactured in the UK - a 630mm pipe for the Dunbar Sewage Scheme. The company also expanded internationally, winning large export contracts, including a 277-tonnes pipe supply deal to a customer in Chile.
That same year, Stewart & Lloyds Plastics developed and patented Rolldown – a method for reducing polyethylene pipe for liner insertion - in association with Subterra Ltd. This innovation was later sold to Subterra and has gone on to become a widely used technique in both the gas and the water industry.