I researched out to the comics community via twitter to ask for advice on the pros and cons of crowdfunding V's a self-ran presale, here are some responses I received:
The consensus seems to be that a crowd funder (eg Kickstarter) is a great way to promote your work, its transparent about the costs of the project and how much you're looking to raise, it also allows me to send updates to everyone much easier than a self-led pre-sale. I still don't know if this is the route I will go down for this project (purely based on time restraints), but it's interesting to know for future reference.
Below is a slide from James Lawrences lecture on crowdfunding, specifically on working out the costings:
Discussed the maths (costings) with some other comic creators, and it made me realise how complicated this could be, I was advised that it can be time consuming too to promote and make it worth while.
An option that was given to me was setting a page up on my website as a pre-sale, with a link directly to paypal, to keep it really simple and manageable, with little pressure to hit a target in a certain time scale etc.
I think for my first two comics I will go down the pre-sale route, and for further projects (or even reprintings), where I have more time, I will go down the crowd funding route.