If your lawyer is telling you this, I would suggest they don't have a very good understanding of either property law or planning regulations 🙂 @Jessica1551
What about local planning regulations for STRs, business licenses and tenancy clauses preventing sub letting?
Most landlords (myself included) have clauses that prevent tenants from sub-letting rooms in the place they are renting. It doesn't matter whether you go through estate agents or find your prospective tenancy through other means this will still be an issue for you.
There seems to be a growing number of so called expert hosts and others who promote their training courses and books advocating becoming a host through renting somewhere, when the reality is that unless you have a personal connection or find a hard to rent place this is unlikely.
If you want to get into the game, why not offer your services as a co-host while you build up resources to buy somewhere.