A pool is exactly as it implies: a slower, deeper and wider part of a river. Pools are linked by narrower, shallower sections. These are known as rapids, glides or runs. In the upper reaches of a river pools are closer together and are linked by short rapids. Pools get further apart as the river gets closer to the sea. In large rivers they are almost nonexistant in the lower reaches.
Hi Matthew. Sorry to hear you're still a Barbel virgin. I've not fished the Ure much and don't know Kilgram Bridge. I've got 12lb Sensor Clear on my reels at the moment, but the 10lb should be fine for most situations. Drop me an email and I'll take you on the Swale for a day.
If you check the "Actual" breaking strain of that 10lb Sensor Daiwa you will almost certainly find it breaks nearer 13lb not 10lb as the label says. Enough for any river I would have thought.
Sensor is one of those lines where the real breaking strain bears little resemblance to the stated breaking strain, 4lb breaks at 6lb, 6lb breaks at 8lb, a difference of 50% and 25% respectively. No it doesn't make much difference but it is always nice to know especially when attaching hook lengths.