Taking our cats back to Dallas

We're returning to the states and taking all 5 our kitties back with us.

I'm sick over the price.

Any suggestions? What to do?

Giving them up is not an option.

We brought all 5 here and thought that the price to return with them would be less as there's less work and hassle on this side. Boy was I wrong.

Route is EDI to DFW.

Not sure what the question is? 

If giving them up is not an option, then what's left?
Cough up the money and take them back with you, or... dont move back to the US.
Unless I'm misunderstanding your question, those are your options. 

Less expensive alternatives than my current, high priced option of BA from EDI to DFW.

Anything that anyone else has done to reduce the cost of moving their pets?

Sailing on the Queen Mary?  This really is the only other option rather than air travel, but I am not sure of the costs.

You should be able to check them in as baggage on some airlines going back instead of as cargo.  I know that baggage does not sound pleasant, but I use to check one of my cats in as baggage when we travelled throughout the states, and she was well taken care of.
They did not let her out of the crate, but they gave her food and water when they could, or when they had the opportunity.
Since you have 5 animals, it will be expensive.  Different airlines have different rules.  From what I understand some may require a cargo flight doing back to the US, and some still offer the baggage option.  Can you try different airlines ?  It is still going to be expensive with pets checking them on as baggage because they are higher priced then just checking in an extra piece of luggage.  
I know some people who have been very pleased with United Airlines with pets as they go back to the States.  I am not sure of your situation or if you are required to stay with a specific airline on your travels home.  You also do not have to ship them as cargo coming back to the States.  You have several options when bringing them back