It saw a 16.9% jump in annual sales for the year to the end of February 2024 with sales of nearly £11bn.
It’s 30 years this month since Lidl arrived in the UK. It now has more than 960 shops and is the nation's sixth biggest grocer.
Mr McDonnell has been with the firm for most of it and remembers the early no frills stores packed with unfamiliar products.
“I remember selling pallets of more continental products. We’ve come a long way, evolving our ranges," he said.
One of its quirks is "the middle of Lidl" and a trip to the retailer has become synonymous with shoppers returning with something they had not gone in for.