If there is a monster surge because of an open gate already being in the location where the mythos card says the new gate chould open and the monster level has already been reached in Arkham can monsters appear on gates in Dunwich? (I assume not because that would mean that a Dunwich gate would 'surge' more monsters than the 'surging gate' in Arkham BUT what if the monster limit is just about to be reached? Do I then place those extra monsters above the limit in Dunwich as long as they only get one monster each before sending any others to the outskirts?)

Yep, you're not allowed to place all monsters on expansion boards, simply because monster surges requires you to split monsters as even as possible between the gates. Let me make you an example, in order everything's clear. 2 gates in Arkham (Woods and Wht Witch House), 2 in Dunwich (Wizard's Hill and Whateley Farm) in a 6 players game. The surge is centered on the Witch House, and Arkham has already reached the monster limit. You should place 6 monsters on the board. The first monster you place must be on the surging gate. Limit reached, so the monster instead of being placed on the Witch House goes to the Outskirts. Same stuff for the other gate in Arkham, then the gates in Dunwich receive one monster each. You still have 2 monsters to spawn. The first one must be placed again on the Witch House (the surging gate may not receive less monsters than other gates) and thus is put in the Outskirts. But you can choose where you want to place the 6th monster between the other three gates.

Hope this helps!

Many thanks. I have been playing the game since Christmas a couple of times a week and have yet to play it with all the rules ironed out!. Every now and again a situation arises and I am unsure of the exact procedure to follow. This forum and its members are so helpful. The amassed gaming experience is immense and someone is always ready to help out us newbies who might be blinded by the multiple and varied experiences of the Arkham/Lovecraft Carnival.

You're welcome