Greggs (LON:GRG) shares got off to a volatile start on Tuesday morning, after disclosing mixed results for the six months to July 1st.

Changes to the menu led to a significant increase in sales over the first half, up 7.4 percent to £453 million. Company managed shop like-for-like sales rose 3.4 percent, boosted by breakfast deals and healthier options such as salads and cold pressed juices.

However, net cash inflow from operating activities fell to £34 million from £44.7 million the previous year, and the firm ended the period with a cash balance of £19.9 million.

Pre-tax profit in the six months to 1 July 2017 came to £19.4 million, compared to £25.4 million the same period a year ago, due to exceptional costs of £8.7 billion for its overhaul.

The group have left their previous guidance for the full year unchanged, howevr, with the overall cost expected to arise from the reshaping of the business remaining in line with expectations.

Roger Whiteside, chief executive, commented: “The business has traded in line with our plans during the first half of the year. We have made good progress with our strategic plans and remain confident of future prospects although we remain alert to short-term pressures on consumers’ disposable income. Over the year as a whole we expect to deliver results in line with our previous expectations as well as further progress against our strategic plan.”

Shares in Greggs surged at market open, before sinking back to below their opening price. They are currently trading down 0.09 percent at 1,10075 (1053GMT).