They haven't got a USA licence either, but that doesn't stop them taking USA players.
IMHO only a few softwares are actually bothered about the UK licencing issue - the likes of RTG, Rival, BetOnSoft, SlotLand, etc who have been ignoring the USA, France, Spain, etc "bans" in the last 8 years are very likely to take the same stance with the UK.
KK
We can't be absolutely certain, but in any case, there is nothing in the new rules that prevents a casino from paying out on bets made prior to 1st October.
Many softwares, including the likes of Microgaming, DID ignore the USA ban when it first came in. They only scarpered when things got too hot for them. In contrast, many are scarpering BEFORE the new UK rules come into force, so maybe it's the threat of blacklisting software suppliers that operate in black markets as well as operators that has made them act differently.
Slotland is a small target, so might err on the side of caution as many of the casinos applying for a UK licence are of South African origin, even though they use a Malta based subsidiary for the EU.
RTG may not care, but Club World, iNetBet, and a few others are UK based companies. This makes them a very easy target for the UK authorities. They may pull out of the UK if they feel their B&M HQ will come under scrutiny. They may of course relocate instead.
There may also be the feeling that the UK has started a trend towards licencing at the point of consumption, rather than the point of supply, and the rest of the EU might follow our lead because it would be a fresh source of tax revenue.
One has to remember the disaster that nearly brought an end to GoWild, when it's offices got raided even though they were only offering the gambling to customers outside the country. It took one miffed employee to set the whole thing in motion.
Casinos that want to flout the UK rules will have to house everything in an unreachable jurisdiction, thus relying on how notoriously difficult it is to police the internet. Even Rival has the problem that whilst everything is in Curacao, and out of reach, the owners are in Canada, and would be within reach.
We will just have to see which casinos are scared off after 1st October, even though they have no assets within the EU.