Brake cleaner is a powerful solvent and highly flammable the breakdown guy was using it as a starting aid. WD40 isn't in the same category so t won't have the same effect. It sounds very much like the fuel system is drawing in air at some point and it could be either at the fuel filter or one of its connections. I suggest you double check the fuel lines which where disconnected during the filter change. If this makes no difference it may well be worth spraying some spray grease round each connector as this may act as a temporary seal and although not a permanent solution i tmay assist in detecting the exact problem. When reconnecting the fuel lines it isn't easy to check if they are prooperly secured. Just because fuel isn't leaking out doesn't mean air ain't getting in. Check to see of you fuel system has a priming bulb and if so give it a few presses and see if it starts firt time.