Practically the only churches that are increasing in Europe are immigrant churches. Even if you focus on those few that are growing slightly I find it disingenuous. The fact is that many tens of millions have stopped going to church all over Europe. Finding a few isolated churches that mainly consist of new arrivals from Nigeria and Ghana that have grown by a few thousand are small by comparison and don’t contradict the overall trend.
This is all documented in Field’s book about Britain in particlar. The big churches have lost millions of members: Anglican, Methodist, Baptist, Presbyterian. A few small Pentecostal churches have grown slightly. It’s like losing a wallet with £100 but looking on the bright side that you found a 50 pence on pavement. The overall trend is clear.