I have recently purchased the 1mm Sheet Wax and every time I try to produce a mould using this product it comes out with pinholes and surface imperfections as seen in the photo below, (I do make sure not to cause any damage, or unnecessary holes when laying it), plus, the wax is sticky and hard to remove. Any idea as to why? 

I have been using Tooling Gelcoat and Polyester Resin for Fiberglass Reinforcement.

I have also been following the proper steps as seen in the video.

The wax will not deliver a perfectly smooth surface, although careful application will usually mean the minimum of flatting needed afterwards, followed by compounding and polish afterwards if a gloss finish is required. It will also very much reflect the surface it's being applied to, so any slight lumps and bumps underneath will transfer to the mould surface afterwards

Looking at your picture, it does look like you've not quite worked it into the corners and they appear somewhat bridged. The wax works better if it's slightly warm and it can usually be conformed to most shapes, but tight curves can be challenging. It is quite normal for it to stick itself to the mould surface afterwards, though and it can be a pain trying to scrape it away. A heat gun can help, though, with lots of mould cleaner afterwards for the smaller bits

Freeman (the manufacturers of his wax) actually make a sealer that this wax is supposed to be sealed with prior to moulding, hence why it sticks to the mould afterwards. I like to spray any sheet wax I use with a thin coat of PVA release agent - as Mark mentioned, the sheet wax doesn't leave a fantastic surface finish anyway, so spraying it with PVA doesn't make it any worse but it does help with removing the wax cleanly.

Other than that, warm it up with a heat gun and scrape it off the mould with a wooden or plastic spatula, then clean the residue off with mould cleaner. It's pretty tedious to be honest, I hate sheet wax - but it does fulfil it's purpose well.

Is it a cover of an existing part that you're looking to make, were you using the wax to cover up a poor surface on the original part or, perhaps, just looking for a reliable release?

If you're looking to make a cover for the original part, an alternative might be to skin it first with a layer or two of fabric to build up the necessary size difference. Of course, this would take some work in terms of the flatting and finishing, but you should be able to get a nice surface from which to create a good mould. If the shape feels a bit challenging to skin neatly, especially around the corners, you could try using fibreglass mat, but this might be harder to judge in terms of getting a fairly consistent thickness and would likely require some filler to help get things smooth before coating

If you're just looking to improve the originals surface, then priming and painting might be the best route forwards. Just be sure to use products that will reliably stand up to the moulding process. EC sell several products that can help coat patterns well and, with careful application and finishing you can achieve a great mould-friendly surface

Appreciate man.