Under sink shelf.. template?

[Music Man]

My new (to me) T5 SE doesn't have a shelf in the cupboard under the sink and I'd like to have one as I'm not planning to have a Porta Potti in there. I've posted on "wanted" to see whether anybody has one to sell. Failing that, I'm planning to get a piece of Dibond cut to roughly the right size (I've been told this is what the original shelves are made from) and then shape it to fit nicely. Thought about buying the Brandrup anti-slip mats so that I have a template (and some anti-slip mats I suppose!) but at £40 they seem an expensive way to go. So, does anybody feel like pulling out their own shelf and sending me the measurements, or even some kind of template?