Advice on field maple pruning/ramification

Hi there,
I've just bought a British field maple bonsai (Acre campestris) and am after any tips on how to increase ramification. It is very bushy with large leaves which are currently hiding a very nice trunk (which was the main reason I bought it)

I am used to trimming back chinese elms to promote smaller leaves but have no experience so far with field maples. My issue is on closer inspection there are a lot of single large leaves on long stems but there not many smaller leaves near the base to cut back to. Should I remove all the larger leafs on long stems?

I've just received the bonsai through the post so am allowing it a few days to get over any trauma of shipping although it appears very healthy. How long should I wait to begin pruning and how much can I get away with taking off in one go?

Thanks

Pics:
https://imgur.com/a/IZ3uH
(The last pic on the album is from Kaizen bonsai where I purchased it and it shows a much neater looking tree)

I am sorry i can,t tell how to prune,,, I just wanted to say you got a very nice tree there !!!!! hope some one will help you out.. post it when you work with it please.. super tree.. take care john