After the holy grail: inexpensive, formal maternity work wear for plus size ladies

[Makingnumber2]

As the title says- where can I find inexpensive, formal maternity work wear for plus size (I'm size 18) in UK?
I have no choice but to dress formally for work and anticipate needing maternity wear sooner than I did with my first (baby due mid October).
I've looked at H&M and New Look but majority is either leggings/trackie bottoms/jeggings/jeans.
I have to be in formal office wear including a suit jacket for work.
I do not have budget for Seraphine etc.
Any shop suggestions and also any outfit suggestions/capsule wardrobe item suggestions really welcome- TIA!

Pretty limited on choice for style of formal wear.
Try New Look, H&M, M&S. You could try places like ebay for 2nd hand ones to keep costs lower too.

Honestly Seraphine is pretty good for work stuff - maybe have a look on ebay or at their sale? The prices can be comparable to cheaper shops for new (although still costly to be fair!)

Could you get some standard maternity wear tops/trousers/dresses in plain colours that you can mix and match and add a non-maternity jacket to make it more formal? If you get one of the ones that isn't meant to be done up you can keep wearing as your bump gets bigger and it'll still be something you can use after baby is born? Or do you need an actual suit jacket that buttons up? If so I have no idea!

Jojo Maman Bebe do lots of nice work dresses. Often available hardly worn on eBay or marketplace.

Here's a maternity blazer
www.zalando.co.uk/love2wait-blazer-black-lw229k004-q11.html

If you're on a budget I'd look on eBay and other places for second hand.

ASOS have some decent options
www.asos.com/women/suits-separates/cat/?cid=13632&currentpricerange=5-250&nlid=ww|clothing|shop%20by%20product&refine=attribute_10155:6400

And you could try Next too

I've been having a look I'm not ready for maternity wear just yet but heart yours and Dorothy Perkins seem to have nice maternity clothes and a bit dressy aswell

I bought stretchy dresses from phase 8 off eBay second hand for work.

Try yours clothing. They have a maternity section but I got a lot of smart dresses that were a jersey material that worked well with a maternity vest/camisole underneath. Very reasonably priced.

Thanks everyone for your suggestions so far I've found some cigarette maternity trousers in h and m and another pair of ankle length trousers with a waist tie in Asda George- can probably get away with one of my existing blazers/suit jackets (it doesn't have buttons) until my back and boobs increase (which happened with #1) and then need some jersey tops in a few different colours to mix and match. I've also remembered I have a stretchy black skirt from first pregnancy that i will prob get away with with tights for when weather gets cooler.
I had just forgotten how pricey getting the maternity bits was tbh- need new nursing tops and nursing bras too. Should have timed baby 2 better to arrive in same season as baby 1 did then I could have re-used more I think.

Dorothy Perkins have a big sale on right now, they have some formal maternity clothes. I've just bought a bunch and I'm not due until October either, got to a get a bargain while it's going!