Before buying anything, check if your current Heat Link is part of the known Nest 3rd Gen recall/replacement program .
If you aren't eligible for a free replacement, you'll need to look at secondary markets. Learn about Heat Link for Nest thermostats in Europe buy nest heat link
Finding a Nest Heat Link on its own can be tricky because Google typically sells them only as part of a complete thermostat kit in Europe. Before buying anything, check if your current Heat