Looking for some help on choosing a platform on which to build my store, it is a online tailors and the most important thing i need is a way for customers to be able to build there own suits/outfits, with a visual representation as they go.
So for example, first they pick a shirt, then be able to customise it (change pocket type, button type, colour ect) with the image updating with the changes.
Is this something that could be feasibly done with an off the shelf platform, or am i going to need a custom made solution?
You can choose magento ecommerce platform for such customization. This will be best fit for the example you have shared. Multiple other options like if your customer changes the button type, then the price may differ which will be possible with Magento.
You can try Drupal as one of my friend having a business of handicrafts and he also wants that his visitors customize the things like carpet colour, material would be select by the visitors themselves. Now he got a website and getting good traffic and ranking in SEPRs also as drupal provides website in multi languages and seo friendly too.
I would also first contact the store owner and ask for reference. if not help, i would check with developers and ask them to evaluate and/or suggest the platform. Each developer has its own preference. or you may go with some freelance site and ask for quote & platform altogether.