You don’t really get paid for going on Grand Designs, but some people use it as leverage to get freebies and discounts from suppliers.
Knowing what the programme makers are after, I’d never go on it - either as a punter or as a client’s Architect. They deliberately look for schemes that might go wrong, filtering out those who are competent or who have employed a full design team. Even if it goes well they then usually edit it to inject jeopardy.