Revenue climbed 3% on a like-for-like (LFL) basis at FTSE 250 gambling group Rank, driven by the performance of its Grosvenor Casinos brand, but weakened by smaller improvement from its Mecca brand.The overall gains, which were made in the 15 week period to 12 October, were thanks to an increase in customer visits and higher staking levels at its Grosvenor casinos, with increases seen across the UK, with particular strength evident in London.The performance of the London venues resulted in total venue spend per visit growing by 1% in the 15-week period, despite a slightly lower win margin.It reported an improvement on the digital side of things, saying its growing customer base was being driven by cross-sell from its venues.Mecca climbed just 1% on a LFL basis, while total revenues for the brand were flat, with an increase in spend per visit offset by a reduction in customer visits.The result was in line with the group's expectations and it remained confident of its full-year outlook.Chief executive Henry Birch said: "The group has had a good start to the financial year and I am pleased with the improvements seen in our Grosvenor Casinos brand, particularly in its digital channel, and the actions to strengthen the performance of our Mecca brand are showing some positive signs."