Well...

...the $1400 people -- professional packing, collection in Tampa & delivery to our door in Leeds people emailed me back saying it's still not too late to go with them.
We started toting up our extra costs on the $675 quote from UPakWeShip...we'll need to purchase packing supplies (good boxes--not an old toilet paper carton scavenged from Kash-N-Karry, bubble wrap, foam peanuts, tape, etc etc), shuttling stuff to and from near the Tampa airport in a small rental car (gasoline!), rental van/truck hire over here plus petrol for going to collect in Eccles-Manchester... And that's assuming my stuff is less than 35 cu ft, which if it's more than & I'm thinking it just might be...the UPakWeShip price is going to be even more yet...
For a few $$$ more, we can have the whole thing done for us -- leaving us more time to play in beautiful, sunny Tampa Bay on our 'holiday'...
Steve said - Yes! (just waiting to hear back to see if we can agree a collection date & what they need from me)