I had those surgeries in 1997 by one of the Viel twins. It was a disaster. Over the years I've encountered several UK based patients who have had the surgeries and I don't think I'm aware of a single long term success story.
Personally, I don't think fat is an ideal filler, especially with now with the advent of synthetic fillers, such as PMMA, Ellanse and HA.
The lengthening surgery tends to be of limited success. Flaccid gains are usually recognized, but for erect gains, post op stretching is needed and it's far from clear if these gains are achieved at a faster rate than those seen by guys who stretch without having the lig cut.
Have you consulted with any Dr's yet and if so, who?
Personally, I think Moorgate appear like an absolute bunch of cowboys. I wouldn't let them near my penis.
Over the years I've found plenty of guys willing to talk about their fat transfer procedures and most aren't thrilled. However, it is rare I've encountered guys from the UK, though we do have a few on the forum.
If it's the U.K., look into Androfill, they offer both Ellanse and Hyaluronic Acid (HA), fillers generally regarded as good options for Girth enhancement. I would have recommended Mooregate, but they continued to shill my forum well after receiving warnings & suspensions. Good luck.