Tummy tuck may be overkill
Liposuction alone may be all you need since the skin tightens up a fair amount with liposuction. It is good you have lost some weight already but loosing more weight won't change the outcome of the liposuction so get it done now and forget the tummy tuck. Cost is roughly $5000-6000 for the abdomen and hips.
Although I don't have a clear picture of your abdomen, from what I can tell you have fat around the abdomen and hips at the very least. You don't appear to have much in the way of stretch marks and I can't tell the condition of your abdominal wall.
I would consider a two stage operation doing the liposuction of those areas and see what you get. You still may need a tummy tuck but I think the results will be much better. You will have a greatly shortened down time from lipo alone and your results may be so good you opt not to have the tummy tuck for several years.
Before deciding what to do I would see several plastic surgeons in London and then make your decision.
Steven Schuster MD FACS
You definitely are a good candidate for a tummy tuck as well as some Lipo on your waist and hips. I don't think you need to lose weight before your surgery. Most importantly, do not gain weight after surgery. That is the problem many patients have which leads to dissappointment.
Lose the weight first before having a tummy tuck
It is always best to lose the majority of your excess weight prior to having any type of body contouring surgery. The more weight you lose, the more skin your surgeon can get rid of, the better your results and the better you will feel about yourself. With a tummy tuck, the more weight you get off, the lower your scar tends to be. Patients who try to have surgery first to 'kick-start' themselves to lose weight, generally never get down to their ideal weight. Use your surgery as your incentive to lose the weight first.
Weight loss before tummy tuck
It is in your best interest to be as close to a "long term weight" as possible prior to surgery. This will give you the best chances for a good surgical outcome and minimize chances that revisionary surgery will be needed in the future.
In regards to the "muffin top" you mentioned, you should be aware that often liposuction alone is not sufficient. Sometimes an extended abdominoplasty (excision of excess skin and adipose tissue of the flank and/or back) is necessary to achieve the desired waistline. Make sure you are working with a board certified plastic surgeon experienced with all types of abdominoplasty.
Weightloss prior to surgery
It is important to be within a few pounds of your ideal weight prior to surgery. This weight should be maintained for several months before having a cosmetic procedure. I would suggest consulting with a board certified plastic surgeon for a consultation. Upon examination, your surgeon would be able to recommend the treatment options which would best address your concerns. Best of luck!
It is always better to loose as much weight as possible before having liposuction. You will also want to tighten the muscle as much as you can. You may even be able to do all that without surgery!
Weight loss before tummy tuck
You should almost always try to be at the weight you are planning for prior to a tummy tuck. You can expect some weight loss with the procedure but not a substantial amount. When you have the tummy tuck at a stable weight you will be most likely to have a good long term stable result.
If you have a tummy tuck or liposuction or both, you should be at your desired weight first
It is hard to tell how loose your skin is from your photo. If when you sit down and the skin rolls up in folds, you will be best served by having liposuction and a tummy tuck combined. As to the correct weight for the surgery, it is up to you. If you feel this is the best you can do then go for it now, if you can loose the extra pounds before surgery it would be best. You would get a better and safer result. If you loose too much weight after the surgery you certainly would have wished you had lost the weight first.