@ChrisBarnes, Since I am newly in the market for a replacement oven the recent tests are timely and educational.
My present oven is a 75cm model that is really 74.5cm in its 75cm cutout. I cannot find any 75cm model that is only 74.5cm although I found one model that shows 74.5cm on its spec sheet. Getting excited about a perfect replacement (choice of 1) we went to the shop but alas it was actually 75cm. I suspect a few years ago the size may have referred to the product or the hole. Because of (errors? age? changes?) at least one manufacturers’ Claimed external dimensions (mm, HxWxD) on their spec sheet are not correct against their current production. This can be compounded by the numbers of variations in pdf and print that are superseded but remain in the wild. Although one is warned to always measure the product in one’s hands prior to cutting holes, when the hole is already cut and you need something that fits, it is a slightly different problem.
Moving ahead I expected a 70cm to have more useful cooking capacity than a 60cm, but from the review see a number of 60cm have more capacity than at least one 70cm, so it can be a bit of work to decide what best suits your pans - until you buy new pans that are different.
However, among the many useful points in the review is Internal baking dimensions (mm, HxWxD), but what is that? Is it the shelf area (WxD) one can put trays on? Is the H from the bottom shelf to the top of the oven cavity, or floor to top? I could take a measurement to a shop and find out, but this item has a lack of clarity in its otherwise noble attempt to clarify the usability and shown as Measured internal baking volume (L).
Would you please clarify what the internal baking dimensions, apparently measured, measure?