I had a similar idea (having one of the mortgage brokers I know underwrite any prospective buyers.

You didn't mention where you are operating, but depending on average home prices, I think you'll be ok.For instance if we're talkin $500k homes, and if you will get a 2.5% commission, split that 50/50 with your Broker, you will end up with $6,250 per sale, right?

I don't know a single broker who would allow an agent to wholesale while hanging their license at their firm. 

Risks: rates go down and you have to pay a prepay of 2 or 3 %; you have to sell and pay the prepay; rents decline & you can't make the payment like any other type of loan; cost upfront a little more than conventional; need to find experienced broker licensed in the state where subject property sits; servicers are bulldogs. 

I'd talk to brokers in your specific asset class and market.Do you already own similar assets?

Here in the USA you need what's called a "construction loan" and it's also very hard to find a company that will insure you if you're a newbie.

I know broker fees are $500 so $12,500 in commission?

I currently broker LIHTC multi-family for a large firm coast to coast and am also interested in MF in the Arizona submarkets as well, and will eventually invest on that scale - I just figure breaking into the state through SFH flips may be a more risk adverse way to understand the pros and cons to phoenix submarkets.

Why should the broker/seller take you seriously?

With 20 years experience managing my sfr and as a property manager for a broker and a bank, this switch into ABNB has been a learning experience.