I'm new to BS code and I'm modeling a building with notional and wind loadings based on BS 6399-2:1997. However, I' was not able to find the code specified limit to check the lateral displacement.
It depends on the building and construction type; BS5950 Table 8 has some guidance for steel buildings.
For portal framed shed type buildings H/150 can be appropriate.
Serviceability limits are not usually mandated but are left to the engineer's judgement.
I think I it is a good idea for me to use UBC 1997 to check the drift which requires the engineer to include P-Delta analysis + cracked section properties.