I use parcel2go for my deliveries. On small items this usually defaults to Hermes whilst large items go via Parcel Force. I have used them to deliver and ollect awnings and some heavy tools. I've put in 2 x 15kg parcels at 130 x 35 x 35 cm. It comes out at about £30. Wrap the awning bags up in a couple of black bin bags, you print the labels off and take to a Post Office counter. Insurance is at extra cost to your needs. PM me if you need more advice.
Do NOT just take them to the counter and pay there. The cost will be far higher.

Colin

Nothing major to cover. Basically it would be filling in questions and answers. I don't know if the OP has used P2G or how good they are working there way around some websites. If they are like me they might welcome a bit of advice.

Colin

I think the problem will be awning is over 15kg and as mentioned above this is the Hermes max .It may be possible if the contents of the two bags can be juggled so neither exceeds 15kg. This is why I use P2G website as it seems easier to input the information and is less of a headache.

Colin