What would be the best way to try to get these started?
Should I try to source some larva somewhere or what would you recommend?
Attracting BSF can take some time but I think it's better than buying them. Compost piles are great BSF attractors, especially if you process a lot of kitchen scraps.
I got most of my eggs to start this year from an established compost pile: LINK
Here's my post about the basics of attracting BSF: LINK