Design me a Product

I manufacture and sell a range of vehicle fitted racks. Batch size is generally 100's. I do the design work and currently do the detailed drawings by hand which are then put into a CAD system for manufacture. The manufacture is laser cutting - on tubes and flat steel (stainless and MS). Most production is in UK with specific items coming from China. I want design assistance to detail out the parts, to assemble a CAD model of the product to ensure all fits together and there are no overlaps or problems. I want to be able to use an enhanced CAD model to improve the web site. For most items I have already mocked up working units to prove the system will work. There are videos of these models. There are few curves and no complex 3D so the CAD work is simple. I am happy to have the work done anywhere in the world and I currently get CAD work done in India - but the Draftsmen are simple CAD workers with little understanding of the function and fit of what they are drawing. I would supply working sketches of the items that make up the assembly - but a bright inquiring mind will probably come up with ideas to make the assembly better. I would pay at an agreed hourly rate with weekly invoices paid immediately by Paypal. I reserve the right to terminate at any point I feel cost is outrunning benefit. I am looking for a competitive hourly cost (so the Freelancer hourly rate indicates the maximum )as there are a string of projects to be done and if the relationship works successfully then it will extend almost indefinitely. The chosen designer needs to be able to converse in English - probably on Skype. The uploaded Final_assly file is only indicative and shows an older product.