Enhance UX for OpenCart Parcel Lockers

I have OpenCart with Journal theme and Equitix Quick Checkout module.

Current situation:

Omniva parcel lockers are displayed correctly (grouped in one list/dropdown).

Other carriers' parcel lockers (LP Express, DPD, etc.) are broken:

- each locker appears as a separate row
- not grouped into a single selectable list
- UX is bad and confusing in checkout

What needs to be done:

Fix grouping logic
- All parcel lockers must be displayed as proper grouped lists
- Same UX behavior as Omniva
- One list/dropdown per carrier
- No “one locker per row” rendering
- Add search/filter input for each carrier
- At the top of each locker list
- Text search (city/street/locker name)
- Instant filtering while typing
- Must be clean UX (not hidden, not popup-hacked)
- Checkout UX quality

Everything must be:
- clearly visible
- logically structured
- not hidden in modals/popups unless UX makes sense
- optimized for real checkout flow

No “technically works but ugly” solutions

Post-fix review

After implementation:
check full checkout flow
adjust anything that breaks UX or logic
small refinements included if needed

Tech stack:
OpenCart
Journal Theme
Equitix Quick Checkout

Goal:
A clean, professional, user-friendly parcel locker selection system that works consistently for all carriers and feels like a real ecommerce checkout, not a patchwork fix.