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The engineer will be very reluctant to use any cable you provide as they will be suspicious of the quality of it. The best you can hope for is for him to do your install with a trailing cable long enough for you to then run it through your cavity wall after he's gone.
If you buy your own cable subsequently, you need satellite grade coaxial cable and f-connectors (not standard tv cable connectors). But this is not recommended as changing the length of cable in your set-up alters power levels in the circuit that can degrade your service, and possibly your neighbours too.
I had a complicated install which involved me running cable left by the installer up a wall, through my loft and down again. They should be happy to leave a load of cable for you too.