Greg, it depends on the number of units under your management.

It all depends on how the numbers pencil out.

Depends on the type of GC you're looking for.The guys picking up material early in the morning at HD/Lowes/Menards are unlikely to run a very tight ship or handle large scale jobs.

It can also cause problems when trying to sell depending on if they are FHA approved, or even lendable.  

Sometimes it depends on seller's motivation and reason.

I create a Single-Purpose entity( almost always an LLC, just depends on the state).

I guess I like controlling the material cost myself, that way I can pick the quality that goes in depending on whether it's a flip or a rental.I'm also more hands on the projects also, I'm there on a daily basis and usually do some work myself alongside them. 

If it's owner occupied PMI will depend on the loan product you get.

Depending on the amount of capital you have and what type of investing you want to do in UK, you may want to consider starting here and moving when your investment income can cover your starting costs in the UK.

What will work best for you will depend on your situation and goals.