I need some images photoshopped onto real looking cars

My company is Eye 4 Media and we advertise on vehicles. I have 2 good potential clients who are undecided about whether to go ahead. So I am looking for a designer to help me mock up some designs so these prospective clients can see what it could potentially look like.

We would like the designs photoshopping onto an image of a real car, so the client can see what it could look like in real life. Just an average car with British number plates will be fine, where you can see the side and back of it. The design would be strictly the side doors of the vehicle, back window and boot/bumper; not full wraps. Examples can be seen on our website - www.eye4.media.

Notes:
4 versions are needed for 2 clients, as one of our clients is considering asking 2 of their partners to half fund the advertising, so they'll need joint branding on there. So the 4 designs will be: One new one for client 1, one new one for client 2, a similar design for client 2 with partner branding, and then the same design with just a change in partner logo
The adverts need to look and feel like the company websites, so the adverts sit comfortably with the clients
I have drafted up the basic elements on the attached, but feel free to blend elements and to make it all look smarter and more gelled together
All of the images are scraped from the websites, and they are probably low quality. I don't have any original images, but the final advert will only be small as it will be on the car. None of this is to be printed
Simplicity is key
There is potential longer term work here if the designs work well, as there will be many future opportunities like this.

Please could you let me know a rough cost initially, and then we can discuss. It would probably work that we'd like you to start with just one design, so we can see how we work together, and then we'll move on to the other three if we're happy with the first design.


Thanks
Joe