We used a professional pet shippers to move our chihuahua from Australia to UK in 2016 and I am very glad we did. First, the border people at Heathrow are very nice, but very strict about the paperwork and mistakes are not tolerated. While we were picking up our boy, there was a family very upset because their pet had been refused entry because on the paperwork a signature was slightly out of the box it was supposed to be in.

Also, we had a near disaster when hours before the flight, the airline announced an immediate suspension in animal flights. Luckily, the shippers dealt with it all and arranged an alternative flight.

Shipping costs are based on size, we paid about $3000 Australian.

I am currently in the process of moving my large 80 pound dog and a cat from Calgary, Alberta, back to the UK. I’m doing it myself using Air Canada cargo. They seem to be the only airline I could find that didn’t require me to use a pet shipping company or that fly direct to Heathrow and so will allow pet travel for that distance. In Heathrow my pets will be picked up from the plane and processed by a company called James Cargo, for just under $400 per pet. This is arranged by Air Canada cargo and is not an option not to use them, but I’m totally fine with that as they check all the paperwork and do all the customs stuff. Once you have your airway bill from them and set up a profile on their website you can also upload your paperwork prior to travel (they need 72hrs) so they can precheck it for you.
Once processed the pets are placed in the animal reception centre at Heathrow for me to collect. I am travelling on the same flight also.
The UK government website has a step by step guide for bringing dogs,cats and ferrets into the UK. It takes a while of uninterrupted reading to make sure all bases are covered and provides you with forms you will need for your vet to complete. This needs to be done within 10 days of travel, they need to be microchipped with an ISO compliant chip , have up to date rabies vaccinations and dogs need tapeworm treatment within 5 days of travel.
I fly December 10th and my vets appointments are Wednesday ( tomorrow) and Thursday of this week.
I was quoted $4800 for both pets from air Canada and this based on weight and size of containers. This is an estimate and I am hoping the final bill will be a bit less once they are weighed at the cargo facility. I pay when I drop them off. This also includes the James Cargo portion of the bill. When I requested a quote through a company it was $5000 just for the dog. I must admit when I checked the Air Canada cargo website I had misinterpreted the costing information and so the $4800 was quite a shock but still cheaper than using a company.
I hope all goes smoothly as I am also travelling with my 2 year old son alone but do have a ride and help from Heathrow!
I hope this information helps.

Where in the process of moving our dog from Florida to the UK he actually leaves on December 13th. We are using petrelocation out of Texas.
There are a lot of requirements and we maybe a little different than some as we will not be traveling within 5 days of our dog as we are waiting for my husband to approved for a spousal visa. The dog is also on medication and BA will not administer so he is going Frankfurt first then to LHR. The pet relocation company will then transport him North to my mother’s home. Oh and they will be picking him up from his home in Florida and will take him to the airport
Pet relocation company is also taking care of all paper work and communicating with our vet and coordinating visits so we meet all time frame requirements for rabies vaccine etc.
We also had to purchase a kennel that is approved by the airlines and meets the requirements for his size we are also acclimating him to it.
I think there are many different companies who do this and you should price how much it would cost for you to do independently.
The company we are using is called Petrelocation .
Good luck and safe travels fro all