Contract - building contract - construction - extent of warranties - warranty of fitness of site - warranty that plans appropriate for erection of soundly designed and constructed buildings - whether included allegedly inadequate culvert for diversion of burn - whether contra proferentem rule applicable. Prescription - negative prescription - interruption of prescriptive period - counterclaim averring breaches of various warranties in contract raised prior to expiry of prescriptive period - deletion of averments in respect of certain warranties - reintroduction of deleted averments more than five years after lodging of counterclaim but within five years of deletion - whether claim relating to one obligation had any effect on prescription of another obligation in same contract - whether obligations extinguished - Prescription and Limitation (Scotland) Act 1973 (c 52), s 6(1).