You answered your own question yourself. You need some kind of, "data such as adwords conversion rates, cold calling success rates and things like this which would back up your claims"

Without any kind of data which you've collected on your MVP, you can't make any statements on growth potential that any investors will actually believe.

Without data you're just pitching an idea. While good ideas are needed, the investors need to see that _you_ are the right person to make and sell your idea successfully. You need your own personal data on your own MVP to prove that. You can't just say, "these smart guys from company Y were able to do X growth, so that means I'll get X growth too".