Most of the small scale DAB max operators charge about £200 a month, but it varies as to their coverage plot and the veracity of their Business Plans. (and looking at some applications, they dont have one!)>. However,. as a COMMUNITY station, Caroline may well be exempt. Most of the Mix Licenses have to give 2,3,4 or so FREE slots to community stations - an OFCOM rule.

Compared to the £800k or so to get almost national coverage on the 'old hat' DAB networks, that makes the SS-DAB ones a much easier route for C caroline. But the coverage is much patchier of course.

(all described in my DAB+ book, about £9 a I think.
https://worldofradio.co.uk/DAB.html