I bought mine close to full price and I honestly think Burberry trenches are very well made and cut. I don’t think I need or want any tailoring at all. I say close to full price because I did get a €200 discount from MyTheresa. Other department stores also do buy XXX amount and get X amount off type of events, those tend to also include Burberry heritage trenches.
Other than that, if you like any of the seasonal styles or colors, definitely look into an outlet. Bicester Village had a ton of trenches for 30% off, and if you are a savvy traveller you can find an extra 10% off coupon, plus you can get VAT refund. You’ll end up paying half price. Downside is, even if a classic style appear it will likely be a less popular cut (I saw some westminister-esque styles I think, in olive, navy, and red). I couldn’t resist a good discount and got myself a nice Burberry Brit trench with slightly less details than a heritage trench, with brass buttons, in roughly a Sandringham cut, for just £430.
Anyway, point is. I think Burberry trenches are worth getting. However, deals can be had, and great ones too if you are not picky about details.