I would spend two months visiting auctions and ringing potential customers, you will struggle to get anything in writing for rates until you start, a collection of Renault or DAF from large fleets are not being sold because they are knackered, they are at the end of the contract and will have been serviced to manufacture specs. R&M is not a golden rivet, the workshop will do the absolute minimum to keep the lorry “legal.”
Forget trailers too unless you are going for a specialism. If you lease a trailer it will be the wrong height, weight, length, colour, and your stuck with it for 3 years or more.
You won’t be able to pull a Morrisons trailer with a Maritime unit.