Fruit and regular potatoes. If you're not a fan of rice, you may want to try rice noodles. Experiment as they're not all alike, but I've found a vermicelli that's a really good replacement for wheat noodles.

Edit to add: I will never get the demonization of good old corn on the cob. If you don't digest it well, you can puree it to make creamed corn.

Eat rice or regular potatoes or fruit.

Aside from sweet potatoes & fruit....

Have you tried adding salsa to things - salads, eggs, meat - or just using as a dip for your veggies? I love the stuff and can put down a ton of it. Plus, there are so many varieties (or you can make your own) that it's tough to get bored.

One of my favorite quickie meals is to mix a can of tuna with an avocado and salsa. You've got a bunch of protein, but also fat from the avo and carbs from the avo and salsa. AND throw in a little bacon if you're feeling froggy. :)

Don't forget about plantains or taro! Those will increase your carbs and give you energy.

One average day for me from Crom-o-meter -

2000 cal
Protein 125
Carbs 165
Fat 98

Banana
Yoghurt & Muesli (GF and really high quality ingredients)
Chicken Salad
Stew with steamed vegies
Coffee
Cheese & pickles
2 squares of lindt 85
15g nuts
Cappuchino
Apple
Yoghurt

Thats a lowish carb day for me. If I was going riding, I would have rice on my salad and dinner.

Twice daily have about 8-10 ounces of some starchy potato: white or sweet. That will get you to something like 150 grams.

Carrots also have decent carbs, more than most people think anyhow.

Parsnips have less than carrots but you can prolly get more than you think from them, too.

Sweet potatos are expensive by you? That's odd I think. Anyway, white potatos work just fine; they've actually got more carb per ounce than sweet potato so it's a win win for you.

Fruit. Rice. Potatoes.

Check out Perfect Health Diet for various other starches.

If I were eating that many carbs a day, and wanted it all whole foods, I'd choose a mix of fruit, potatoes, sweet potatoes, and brown rice to diversify my toxins.

If I wanted just one source, I'd choose either fruit, potatoes, or white rice to minimize toxins.

Note: counting the carbs in vegetables like broccoli, cauliflower, kale, lettuce, etc is a novice mistake.

Sweet peas? I think people in the UK like them.

Eat a LARABAR. They're Primal, deeelicious, and usually have an easy 28 carbs (with around 16-20 grams of sugar from dates).

I was scratching my head at sweet potatoes being expensive, but I see you're in the UK.

I eat rice sometimes--not a ton at a time. A typical day for me is something like the following:

breakfast- eggs and a piece of fruit lunch- 1 piece fruit, sauteed greens, meat/eggs/fish dinner- meat stew, with some potato, carrots, onions

My stews are cooked in bone broth and have lots of veggies, a little potato (probably one small potato's worth per person--a few chunks), and a little meat. I find that for my anxiety levels having higher carb at night as opposed to during the day helps me most. As always, n=1 and you should go with what works for you. I like fresh fruit, and that's a good way to get nutrients and some carbs.

The above adds up to about 130g carb with the following: 1 apple, 1 mango (probably harder for you to get), 1 small red potato, 2 medium carrots, 2 cups (raw) kale, which I cook and the volume reduces significantly, 1 cups raw turnips, which would cook down, 1 onion

Sometimes I add non-starchy veggies to my breakfasts as well.

Why would you want to eat sweet potatoes if they come from far away, are expensive, and hard to find? I don't see anything paleo in that. They are only mentioned so often in all paleo books and websites because those books/sites are mostly American and over here (in the US) sweet potatoes are native, grow all over the place, are sold all over the place in huge piles, and are cheap. Being originally from Germany I had to get used to their flavor first, and now I like them occasionally, but they are not my favorite "healthy carb". Anyway, instead of fruit I would focus more on medium to high carb roots/tuber roots. You can get the carb content from websites for diabetics but here are some examples: in 100 g of vegetable are

sweet potato 20 g

white potato 20 g

carrot, boiled 8 g

red beets, cooked 10 g

brussel sprouts 8 g

cauliflower 4 g

turnip 5

cabbage 5

or

banana 23

strawberry 9

cherry 16

As you can see, the carb content differs widely and if you are looking to increase your healthy carb intake I would go with whatever native vegetable is in season and best suits your taste. Sweet potatoes are only popular in the (American) paleo world because they are abundant and cheap and satisfy the sweet tooth.

I do a lot of endurance sport i.e (cycling) & live in the UK. To get my carb intake I use a lot of fruit, sweet pots, rice but also I have Doves gluten free brown pasta made with brown rice, very nice!;o)

I have the brown one because the white version as corn added to it.

Quinoa another one as well.

I could slurp down 150g of rice noodles in 30 seconds flat. Some butter, salt, YUM!

3 cups of safe starches