Hi A.M.,
You need to be careful of which standards the monitor supports. S-video works with separate Y/C (luninance/chrominance) signals, but the chroma (color) portion of the signal is still encoded to the appropriate standard. For the monitor to work on the regular output from a U.K. receiver via the S-video connections, it will need to support the 625/PAL British standard. Many modern widescreen sets will accept multiple inputs, although models sold in the North American market are less likely to do so than those sold in Europe.
Component video is rather a widerangiing term, as there are several different "component" types of connections. If it's a simple RGB component input, then you should be fine, as this bypasses the color encoding entirely. The scanning rates of the picture are a little different, but close enough that the monitor will lock on to a British 625-line picture with no problems.
The power issue is relatively simple. If the unit is designed for 120V only, then you can run via a suitable transformer. The supply frequency is lower here (50Hz vs. 60 in North America), but virtually all modern TVs are designed to run on either, so it's not a problem. You may find that the monitor will already run on 240V, either by flipping a switch or -- more likely on modern widescreen sets -- without any change at all beyond a new plug.
Both the video standard and power supply question should be covered by the specifications in the user guide which came with the unit. Failing that, a quick call or e-mail to Samsung in N.J. with the model number should bring the required details. In fact the voltage question at least should be answered by checking the specification label on the rear of the monitor. If it says something like "90 to 250V 50/60Hz" you won't need a transformer.
Re the surround-sound receiver, the same power supply considerations apply as for the monitor. You'll need to check the label or book. Dolby Surround and Dolby Digital (5.1, EX etc.) are encoded exactly the same way on DVDs here, so the surround-sound will work fine when coupled up to a British DVD player.
If the receiver incorporates a normal FM radio tuner, that will work, and reproduce in stereo on stereo transmissions here, but be careful of the tuning arrangements. If you have a look in the radio section of the "Technical Issues" thread I explained this in detail.
Hope this helps.
-Paul.