We are currently upgrading our 23 year old Tunstall equipment. The equipment had absolute minimal problems for 23 years and we saw that as proof of quality. For us, there were three options: standalone units, digital compatible ‘lite’ upgrade, or fully new equipment and cabling throughout. After much thought and deliberation, we have fully upgraded, but the bridge you mention (the lite option) was considered. We considered different suppliers too.
I can highly recommend the Tunstall team. Everyone from our initial point of contact (who still checks in on us throughout) to the installation project manager, to the team on site – they have all been excellent. We’ve had some difficult contractors recently (not alarms) and working with Tunstall has been refreshing – especially when my time and charity money is precious.