Mandatory pramameters in links not being passed

[ghost]

Just upgraded an old site using Diem to this version of Symfony so we can upgrade the server it's running on to the latest PHP. I've solved a few integration issues from updates but having massive issues with links due to changes in the code.

ERROR: The "/m/:slug/settings" route has some missing mandatory parameters (:slug).

The error stems from some changes to the pattern routing I think, but I'm having real difficulty in fixing the bug. I've upgraded dmFrontLinkTagRoute to use your new getRoute instead of the getRoutes as that was causing issues to, but it gets to

$this->controller->genUrl(array_merge(
array(
'sf_route' => $route_name
), $route_parameters
));

Which is silently failing. I think it's the line $url = $this->context->getRouting()->generate($route, $parameters, $absolute); but I haven't gotten any further.

Any help or advice would be most appreciated.