API Order Latency compared to websocket

I have a good connection to the exchange where via the websocket I'm getting moderately low latency (<0.1s). However when I post an order I have a latency of over a second. I'm based in London and know that exchange distance can cause a high latency but I would expect the effect to be symmetric ie effect the websocket latency just as much. I don't want to waste too much time setting up an aws in Tokyo if this isnt the problem! Any help would be greatly appreciated!

(Infrastructure on my side is all cabled fibre with symmetric bandwidth.)