Why not check out the official documentation, available online ??
UK AIC 80/00 (Yellow 24)
It's in Paragraph 3.2
When approaching the first cleared level and/or when changing flight level in RVSM airspace, aim to keep the vertical speed within 500 to 1000 fpm, do not exceed 1500fpm and ensure that the aeroplane neither undershoots nor overshoots the cleared flight level by more than 150 feet, manually overriding if necessary.