Customise A WooCommerce plugin to show custom dates / times

I have a website using the following booking and rental plugin:
https://codecanyon.net/item/rnb-woocommerce-rental-booking-system/14835145

You can see the plugin demo here:
https://preview.redq.io/rnb/shop/2017-harley-davidson-street-glide-special/

We need to customise the pick up and drop off times to the following:

Sat / Sun / Mon / Tues
Morning pick up / drop off - 11:30am only
Afternoon pick up / drop off - 3:00pm only

Wed / Thurs / Fri
Morning pick up / drop off - 7:15am only
Afternoon pick up / drop off - 4:15pm only

Only the above times should be shown for the selected days - all other times should not be displayed.

The plugin does not have a built in native way to do this.

It must be done so that the plugin can still be updated, while retaining the customisations.

It's simple for someone with the right experience - if you have any questions drop me a message.