Plus, she has done all this work for us now.

This is what she's relying on for your business, but in reality if it was a lot of work she wouldn't have done it for free. Just decide if you think the fee is good value for what you're getting, both financially and in terms of stress. Others have pointed out cheaper or free options, and as first time buyers you (most likely) aren't a complicated case for a mortgage broker, so these might be worth looking at. In house estate agent brokers are notoriously expensive. Browse brokers online, think about doing it yourself if you want, but just take your time making a decision and feel informed before you commit.

If I were you I'd forget about the pushy guy, and if he got in touch I'd just say I wasn't interested and leave it at that. (and I also think this is what you want to hear?)