As far as I know, Stripe SEPA is only available in EUR currency[0], so this nearly excludes the UK completely. At least for us, all SEPA payments were outside the UK. Probably 95% from Germany and Austria, and the rest from a few other EU countries. Not a huge sample size, but we've been running with SEPA for a few months. We did an A/B test for a a few weeks as well, and basically observed no hit in total revenue when we offered SEPA or without it (only cards and PayPal), so that was the main reason we pulled out the plug. Not just the chargebacks.

Another thing I should mention is the async nature of the whole thing. Unlike cards that get authorized/declined instantly, we're talking days or weeks with SEPA. For a monthly subscription, this eats into the first month easily.

Again, we're talking about private individuals here (B2C), typically students in our cases, and as I mentioned predominately from Germany, so YMMV a lot with other customer types or countries.

[0] https://stripe.com/docs/sources/sepa-debit#create-source

Thanks again. These are all interesting data points. There are certainly a lot of similarities between what you're describing and what we were envisaging setting up. The lack of increased revenue when SEPA was available is particularly worrying, as we know in our case that from time to time we get requests from customers who don't use credit cards, and we were hoping SEPA might be a more accessible alternative for that part of our market.

feel free to drop me an email and I'd be happy to answer any questions if you have (see my profile)