Looking at getting some biking jerseys made but want to design my own bespoke, most companies have a template that you just add your name on.

any ideas?

Ta

Just do it. design what you want on a bit of paper. send it to a few chosen manufacturers and they will tell you what is feasible.
Or download the templates, they are free with no obligation. Any deviation from their template may cost you tho!!
Thats what we did. http://www.steppingstanes.co.uk/

I drew our design on a rough template. I used Inkscape (free vector drawing package – google it) to do the drawing and then sent the file to the jersey makers for them to import into their software. Worked well. I used TheCycleJersey and we will probably use them again once we need more shirts…

It does need a bit of skill to use any vector drawing package, but its worth spending time on it…