instance_id not passed on in checkout page

Hi,

I am using Sendle in local shipping across Australia but also internationally. I am trying to pickup the shipping zone to add some checkboxes that the users needs to agree on (check) on the checkout form. I am using:
$chosen_methods = WC()->session->get( ‘chosen_shipping_methods’ )
in all other cases (other than Sendle method) this is returning an array of the shipping method and instance_id associated example: Array ( [0] => flat_rate:14 ) which is used to get the zone name through the instance_id (14 in the example above)
in the case a sendle shipping method selected at checkout then the same array above returns as follows: Array ( [0] => ossmsendle-Premium ) which is missing the instance_id

As such, not able to lookup the correct shipping zone as many of them are using the sendle shipping method.

Is there an alternative way to know the shipping zone_id or name? or
can the array be modified to provide the associated instance_id as the standard ones?

this is really important to be able to scale this and use sendle for shipping internationally or across multiple shipping zones.

Appreciate the help.

Regards
Christian