Fix tutorial workflows

[MetRonnie]

• Map HTML file was broken due to the Jinja2 (?) double curly brackets being broken over lines
• urllib3 requests no longer working with Met Office proxy, used requests instead, which is nicer actually

Check List

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Dependency changes only apply to setup.cfg, not conda-environment.yml (optional dependency urllib3 removed)
• No tests needed.
• CHANGES.md entry included if this is a change that can affect users
• No docs needed
• If this is a bug fix, PRs raised to both master and the relevant maintenance branch.

[MetRonnie]

(Test failures due to swarm build failure)

[wxtim]

Nice.