Dress alterations

Hello. Is anyone able to recommend a very good ie not mediocre/slapdash/just ok, place that carries out professional alterations to clothes, preferably in the London Bridge/Tower Bridge area? I have someone who needs a dress taken in (it's already been pinned) but it needs to be done well. One place on TBR was unable to do a hem properly. Any suggestions appreciated.
Thank you.

I know a place but they are not in SE1. UK Tailors, 38 Mount Pleasant, London WC1X 0AN. 0207 837 9888 – uktailors.co.uk – they do alterations for many of the top stores like Harrods, Selfridges, Austin Reed. I have used these myself a number of times and can recommend them. No affiliation.

Thank you Eileen.

I used Crystal Clean Drycleaners, 89 Tower Bridge Road (green sign, just near the junction with Decima St/Bermondsey St) last year to alter a dress with an unusual neckline/straps and they were absolutely lovely and I was really happy with the result - and price. I advise ringing up first if it's out of your way to check when the tailor will be there so that they can see it on you and know exactly what to do.

Also, we use the dry cleaners in The Circle on Queen Elizabeth St very regularly for cleaning and minor alterations/mending and they are really good (and honest, deducting the cost from the cleaning of money we didn't realise had been left in a pocket). They just unpicked some darts in a shirt that the shop tailor had done too tightly and they have done a fab job; no trace of the darts ever being there!

Hope this helps :)