Everyone else has summed it up very well, but I'll add my two cents worth.....
How to know where those obstacles are is another matter.
That's the $64,000 question! you would need very detailed information about obstacles withing the circling area. Spot heights on your DAP's would be the best indication.
When doing the oral part of my last renewal my testing officer asked me much the same question, but with a downwind of only 10 knots. We both agreed that doing a circling approach to land into wind is unnecessary and dangerous if the weather is marginal. If the downwind or crosswind component is to much for you aircraft (and your skills) it's better to proceed to your alternate.
That's my view from real world IFR flying, however the AIP does state that you can legally circle if you wish to.