I tried to buy denim shorts in H&M yesterday, £20. My pre pregnancy size was an 8 for bottoms, tried on a size 10... no chance! Couldn't get them on! And yet the linen one I bought a couple of weeks ago in a 10 are fine! I gave up and bought two dresses instead!!
I know it's not your question but maybe think about buying some cheap stretchy material non maternity stuff? I bought 2 Large dresses from H&M for winter and wore them to 9 months. Granted, they looked a big baggy up top and not great overall but hey, it was only for a short while!
I do have some mat jeans I am selling on eBay. If they don't sell, I can send them to you and you can cut into shorts? M&S ripped jeans with over bump band.....
Another one for h&m! I have bought maternity and non-maternity from there during my pregnancy. It can be a lot cheaper buying nice jersey dresses from there in non-maternity (got a couple for less than £15) and you wouldn't be able to tell...also get to wear them afterwards!
I bought a nice length skirt that was 3 sizes too big, cheap, looks ace and fits comfy around the bump i say take the time to try some regular clothes a few sizes up. you can get some great stuff for non maternity prices x
I've had a lot of stuff off eBay. It's cheaper (coz it's second hand) but you can then sell it on again after you've worn it. Got some denim asos maternity shorts for about £3 for my holidays, which I didn't mind paying at all! Got loads of good bargains on there, like a chi chi London maternity dress for a wedding for £10 that is still selling online for £70ish. Worth a look!
I didn't buy any specific maternity clothing just adapted stuff I already had to work with a midi jersey tube skirt from missguided (loads of colours and double layered so not see through, can be worn over or under your bump) and a pair of super low rise shorts from top shop a few sizes up from my pre pregnancy size. I couldn't understand the bump band bits on summer maternity clothes, it makes them hot and sweaty to wear and I was sweaty enough without extra unnecessary layers!