What I did was take a look at a selection of reviews of Marylanza Suites on Tripadvisor by families who have stayed there. On the whole, every comment was favourable, with many stating that their kids (of similar ages to yours) loved it.
From what I can gather, daytime activities consist mainly of pool and darts competitions, with a member of staff running them (who, apparently, is great with kids). Every evening there is a "mini disco".
The hotel also has a "soft play centre", with swings, which it says is "for 2-12 year olds".
Hope that's helped and that everything goes okay for you and you have a great time!