heat resistant plaster

[philiped]

Hi I have just installed two stoves one insert and one freestanding the insert is working a treat but the freestanding has cracked all the plaster behind it after one or two fires.I wanted sand and cement for the plaster but was convinced to board and skim by a friend. ( big mistake) have to re do the whole job was wondering would sand cement lime do the trick was thinking 6 sand 1 cement 1 lime also would lime mortar be a good option over the plaster. As it is an old house wouldnt mind leaving a napp finish on the sand and cement and just painting it dont want to go with the commercial heat resistant stuff as plasterer is comming soon and need to get finished quick before wife has a canary