OvertheHill said:
Never ridden a sportive before. Is there any shame in just going around at your own pace or is it a big race
Go at your own pace.
Some will treat it as a race, some in fact think it is a race because you get a number to stick on the front of your bike (which is in fact for the photographer...)
You will find groups riding together and you can get around quicker tacked on to the back of one, but be careful not to get sucked along in the excitement of it in a group which is far faster than you can keep up.
It is 100 miles (or 60-odd or 40-odd, depending which distance you're doing, obviously), so you do need to pace yourself a bit.
Having said that, this year all the hills will be over with after about 35 miles so it should be a nice cruise in the Cheshire Countryside if the weather's kind.