Toilet Flush Sensor Cable Assembly

I need a cable assembly made from our plans for a toilet flush sensor prototype. The assembly involves a combination of flat cable and pre-made cable that we will cut and extend. We have built a couple of basic units but need about a dozen made for field trials.

Requirements: we can provide some of the materials
- cutting and extending off the shelf IoT sensor cable
- Speaker flat extension cables
- will need water proofing

Ideal Skills and Experience:
- Experience with flat cable and general assembly
- Proficiency in working with pre-made cables
- Attention to detail and precision in cable cutting and extending
- water proofing and protecting

Looking for a skilled professional to ensure a reliable and functional assembly. Please provide relevant experience in your bids.
this may be iterative so UK based.