From further analysis of the trades, it looks like so far it is mostly the larger trades in BTC/XMR that have gravitated to Haveno-Reto as the avg trade size for Apr25 Haveno is around 3x the avg trade for Mar25 Bisq.

We also observe the avg trade sjze for Bisq BTC/XMR drop from 0.13BTC to 0.09BTC from Apr to Mar.

Also the displayed liquidity is still much better on Bisq, so the smaller and medium sized BTC/XMR makers have not migrated across to Haveno-Reto yet.