Minibus School Contracts - Profit Margin

[Voyagetr]

Hi guys, new member to the forum looking for some much appreciated advice. I currently run a motorhome rental business but I’m in the process of diversifying into renting out a minibus with driver. 1 vehicle initially with scope for expansion. I’m currently researching school contracts for the local education authority which are won through a tender process. I’m happy with how to work out my costs but I’m at a bit of a loss when it comes to applying the profit margin. Is there a typical figure or range that companies use when applying for this type of work? I would also appreciate any general advice people are willing to offer up to help a company in its very early stages. Thanks.