Any problem with EU > UK > EU (or vice versa) in quick succession?

[twiningb]

I would be travelling on an Australian passport, this July/August, so I don't believe either the Schengen or UK ESTA equivalents will be up and running yet, but if they were, I would have no trouble complying.

My concern would be: If I had an itinerary like (say)

1. Tuesday, arrive CDG (from AUH)
2. go overland to Belgium
3. Thursday, fly BRU>LHR to meet friends arriving from US
4. Friday, fly LHR>AGP
5. Two weeks later, depart CDG (to DOH)

Do Schengen authorities (specifically probably FR, ES and perhaps DE) care about multiple entries in a short period, or exit followed by reentry within a few hours? Do UK authorities care about similar things, if I end up getting a better routing that involves multiple UK entries?

 

[kelvedon]

I don’t imagine there will be a problem. The EU will record you as arriving on Tuesday , leaving on Thursday and returning the next day for two weeks. Overland travel between France Belgium and Spain are simply signposts. Much like crossing a state line here.They may ask you at AGP where you’ve been.
The UK will see it as a 24 hour visit. You can use the e gates at LHR.