I removed a radiator to decorate behind, now I have a leak. What can I do, or do I need a plumber.

If the leak is on one of the radiator valves You will need a pair of footprints or grips and an adjustable spanner Hold the valve in place with the grips and tweak the nut with the spanner. This should do the trick If the leak is coming from the top of the valve where you have shut off and opened the valves. Remove the cap and you will normally see a small nut, give that a small tweak Hope that helps Terry

This is common if valve is only turned on or off infrequently. take off white cap on valve and with a spanner or grips turn small nut clockwise probably abour 1/4 or 1/2 turn this should stop problem, dont tighten to much as valve will not turn off.

best to call a plumber as very easy to cause more damage unless you feel confident about trying to fix yourself