Mix up some All Purpose Cleaner to a 10:1 ratio.

I, and many other detailers use APC for a lot of interior jobs and it's usually far more effective than the bottled interior cleaners.

Get a trigger bottle with a foaming trigger head to put it in when you've mixed it and you'll have a great interior cleaner

You'll also get many more uses out of it at stronger ratios like about 4:1 for door shuts, wheels, arches, chassis parts etc. and at the same 10:1 for use as prewash for very dirty lower areas on the car.

You can go for the 'detailing' stuff like Meguiars All Purpose Cleaner, but we generally acknowledge that the supermarket brands like Tesco's 'Daisy' and 'Stardrops' are equally as good and far cheaper.