1. What Are Cookies?
Cookies are small text files that websites place on your device when you visit them. They are widely used to make websites work, improve functionality, and provide information to site owners. Similar technologies include localStorage, sessionStorage, and tracking pixels.
This policy covers cookies and all similar technologies used by Gridlock Holmes at gridlock-holmes.com ("the Site").
2. How We Use Cookies and Similar Technologies
We use cookies and similar technologies for the purposes described below. We have categorised them by their function.
2.1 Strictly Necessary (No Consent Required)
These are essential for the Site to function. They do not collect personal data for marketing purposes and cannot be disabled without breaking core functionality.
| Technology | Purpose | Duration | Type |
|---|---|---|---|
| gridlock-current-student | Stores your student login username so progress can be tracked on shared computers | Until cleared | localStorage |
| gridlock-level-1, -2, -3 | Tracks which lessons you have completed in each level | Until cleared | localStorage |
| gridlock-game-unlocked | Records whether the reward game has been unlocked | Until cleared | localStorage |
| gh-cookie-consent | Remembers your cookie consent preferences | 6 months | localStorage |
2.2 Analytics Cookies (Consent Required)
These help us understand how visitors interact with the Site by collecting anonymous, aggregated information. They are only set if you consent.
| Cookie | Provider | Purpose | Duration |
|---|---|---|---|
| _ga | Google Analytics | Distinguishes unique visitors by assigning a randomly generated number | 2 years |
| _ga_* | Google Analytics | Maintains session state for GA4 | 2 years |
You can opt out of Google Analytics on all websites by installing the Google Analytics Opt-out Browser Add-on.
2.3 Advertising Cookies (Consent Required)
These are used by advertising networks to serve relevant advertisements. They are only set if you consent.
| Cookie | Provider | Purpose | Duration |
|---|---|---|---|
| Various | Google AdSense | Serves and personalises advertisements based on browsing activity | Varies |
You can manage Google ad personalisation at Google Ad Settings.
3. Your Consent
When you first visit the Site, you will see a cookie consent banner that allows you to:
- Accept all cookies - enables analytics and advertising cookies
- Reject non-essential cookies - only strictly necessary technologies will be used
- Manage preferences - choose which categories of cookies to allow
Non-essential cookies are not set until you give consent. Your consent preference is stored in localStorage and lasts for 6 months, after which you will be asked again.
You can change your cookie preferences at any time by clicking the "Cookie Preferences" link in the Site footer.
4. How to Delete Cookies
You can delete cookies and clear localStorage at any time through your browser settings. Here is how to do it in common browsers:
- Chrome: Settings > Privacy and security > Clear browsing data
- Firefox: Settings > Privacy & Security > Cookies and Site Data > Clear Data
- Safari: Preferences > Privacy > Manage Website Data
- Edge: Settings > Privacy, search and services > Clear browsing data
Please note that deleting cookies and localStorage data will remove your learning progress and any saved grid layouts. This data cannot be recovered.
5. Third-Party Cookies
Some cookies are placed by third-party services that appear on our pages. We do not control these cookies. The third parties that may set cookies through the Site include:
- Google (Analytics and AdSense) - Google Privacy Policy
- Netlify - Netlify Privacy Policy
- Cloudflare - Cloudflare Privacy Policy (may be used for CDN and security)
We encourage you to review the privacy and cookie policies of these third parties.
6. Children's Privacy
Gridlock Holmes is designed to be used in educational settings, including by young people. We do not set non-essential cookies for users who have not consented. The localStorage data used for learning progress does not contain personal information beyond an optional username chosen by the student, and this data is never transmitted to our servers. Teachers and parents should be aware that Google Analytics and AdSense cookies, if consented to, may collect data as described in section 2.
7. Your Rights Under UK GDPR and PECR
Under the UK General Data Protection Regulation (UK GDPR) and the Privacy and Electronic Communications Regulations (PECR), you have the right to:
- Be informed about what cookies we use and why
- Give or refuse consent for non-essential cookies
- Withdraw your consent at any time
- Request access to any personal data collected via cookies
- Request deletion of any personal data collected via cookies
To exercise any of these rights, please contact us at jon.ellisdon@gridlock-holmes.com. For more information about your data protection rights, visit the Information Commissioner's Office (ICO).
If you wish to make a complaint about our use of cookies or handling of your data, please follow our Data Protection Complaints Procedure. If you remain unsatisfied, you can escalate to the ICO.
8. Changes to This Policy
We may update this Cookie Policy from time to time to reflect changes in our practices, technology, or legal requirements. When we make changes, we will update the "Last updated" date at the top of this page. We encourage you to review this page periodically.
9. Contact Us
If you have questions about our use of cookies, please contact us:
Email: jon.ellisdon@gridlock-holmes.com
Website: gridlock-holmes.com