Make some changes on our joomla website

We are looking for a Joomla developer who can work reliably and consistently to do the following job for us:
- Change logo
- Modify some CSS (font,…)
- Modify some layout
- Add a background picture
- Change the Main Menu
- Add/Change some modules (also the style)
- We are using DJ League as Sport Management tool. Make some style/layout changes for that
- Add cookies notification message
- Upgrade Joomla and all extensions
- Test all on bugs

Before we choose, we would like to see some previous work.

If this project goes well, this will turn into a long-term opportunity.