Besides the 70 research items listed in https://www.researchgate.net/profile/David-Brose/research, there may be more items at ResearchGate not yet attached to your profile. Here are three methods to find them and to claim authorship (see also "How do I confirm authorship of my publications to add them to my profile?" in https://help.researchgate.net/hc/en-us/articles/14293005132305-How-to-add-research):

1. Open https://www.researchgate.net/profile/David-Brose/unconfirmed (visible only to you). There may be a list of publications for which you may claim authorship, provided these are yours.

2. Search for the titles of your missing papers at https://www.researchgate.net/search.Search.html?query=&type=publication.

3. Search for your name or for the titles of your missing papers at Google, adding site:researchgate.net, e.g.: https://www.google.com/search?q=%22David+Stephen+Brose%22+site:researchgate.net (and use versions of your name for searching, e.g. with initials)

Concerning your second question, see my reply to https://www.researchgate.net/post/How_can_I_delete_a_research_paper_posted_on_Research_Gate.