If it's been laid up for a couple of years, then it will need a service regardless of use. I'm not familiar with the TLDI system, but from what I've read it has an air filter which requires changing. In addition, the drive belt to the compressor, fuel filter (high and low pressure filters), and impeller. Change the gear oil while you're at it.
It's also particular about battery power, so check battery is compatible 850-1000 CCA.
Do that first and see how you get on. Sparks are Champion - RC12ECC. Gael Force Marine in Inverness are Tohatsu distributor so you can order from them. Speak to Nik. Part codes here: Tohatsu parts