Moving to UK, what to do?

Step down transformers are cheap and easily available. In the UK you can try www.maplin.co.uk. You can buy a kilowatt step down transformer for less than 100 dollars.
The turntable might be the only tricky part, but check with all equipment manufacturers as some equipment detects the mains frequency and will not work if it is incorrect (e.g. Mark Levinson)

Overall I would not panic. I moved from the UK to the US a few years ago and changing country is a tricky business ... adapting the voltage on your hifi is the easy bit.

What is good in the PSaudiP300 that you can adjust the hertz, while all other converters give you 50herz

I moved from the States to Paris 2.5 years ago, and was faced with the same problem (110V gear running on 220V). Fortunately some of my equipment (Quad and Revox) is multi-voltage, no problem there. The rest is 110V equipment, Including two 200W/channel power amps. I simply purchased a 2kW 220V/110V line stabilizer transformer (~$200). You can purchase the equipment from www.eastwestintl.com or www.220voltappliances.com. The other thing to remember is, HiFi equipment in Europe, especially high end gear, is a lot more expensive then in the USA. Bottom line, bring your equipment with you and use a voltage stabilizer step down transformer to run it.

However, one thing to consider, and I learned the hard way. Certain US high end manufacturers (Krell for certain in the last ~10 years, and, I believe Martin Logan and others) put a frequency sensing chip on the power input circuit. This senses if you are running 60Hz (US) or 50 Hz (Europe) mains voltage (irrespective if it is transformed down from 240/220V to 110V and will not work if the power source is 50Hz. Krell in France charged me $180 to have my Krell HTS converted when I experienced this problem. Check before you leave!

Very interesting posts I will face similar problem in some foreseeable future.
Seems it would be not worth for me to send my power amp to manufacturer in the future to change them form 110V to 220V for $400 if I can buy 2kW step down transformer for $200. (On the second web page I have even found 2kW for $89!
I have question though:
Is it the some to replace transformer inside amp, and to connect amp through one more step-down transformer, for the sake of sound quality?
Now using your step-down transformer power is traveling through 2 transformers, can you here any difference?

or if possible, if you are there for a limited period of time, store your greatest possessions, and get a set up like the brits do, an affordable integrated, digital front end, speaker etc....and jam away, without worrying about conversion issues. If you are the type of audiophile I suspect, I am sure you would not mind plunging $1,000 in equipment, which you can enjoy and sell off through classified there. The brits seems to be all into that sort of affordable set up, maybe because they are cheap, or because most cannot afford anything more expensive, because, how it was well said, hi end is taxed to death there. I am sure that if you are a regular guy, you will be spending hundreds of USD just in shipping and let us not even talk about damage and hassle potential. So, I would take that course. Leave your gear safe, maybe in your relative's place. Go to GB, enjoy the sounds and sights, and do as the brits do. That is the best way perhaps solve this issue. Check HIFI choice etc...and you will know What I am talking about.

Recommend: Those used A21 Sudgen class A integrateds. They will sound smashing eventhough you might get a decades old unit. Pair it up with an Epos or another minimonitor and you WILL be in heaven. Doubt you will miss your behemoths. If I were you, I might even looking into esoteric European gear that is overpriced in the States as an interesting option. For this sort of gear, I would check HIFI plus, if I am not wrong, that has the same size as a Stereophile magazine, but it has a harder cover and it is not as shiny. They have GREAT reviews of excellent sounding and looking gear there.

Paul