A typical terrace house might have a back wall that's basically a square, with a width and height of around 4½ metres. So that's an area of around 20 square metres. However the actual area to be rendered might be closer to 15 square metres after you've taken out the space used up by the doors and windows.
(I've used this, together with my memories of living in a terraced house in Sheffield, as a guide for those figures:
https://www.researchgate.net/figure/Floorplan-of-an-average-terraced-house_fig1_285235992 )
This site suggests that the cost of acrylic or silicone rendering in the south of England might fall into a price bracket of around £60 to £75 per square metre (with silicone being marginally more expensive than acrylic):
https://tradesmenprices.co.uk/rendering
If we assume an area of 15 square metres, and a price of £70 per square metre, that yields a figure of (very roughly) around a thousand pounds.
However I've got a feeling that this is really one of those "How long is a piece of string?" questions ;-)