This appears to be a case where there are a number of co-insurers with Aviva being the lead office. In such cases, where there is a substantial risk, ie, a large factory, a large apartment block or large organisation ( ie, the GAA), a number of insurers share the risk between them. The insurer who carries the largest porportion of the risk is called the lead insurer and they are the company who instruct the loss adjuster and make decisions on the claim. When the loss is agreed, the leading insurers then approve the figures and each of the co-insurers are copied with details of the overall loss and what porportion they have to pay. Cheques are then issues separately from each of the insurers.
My suggestion to the OP is to raise this matter with the management company and insist that they raise this issue with the brokers who arranged this cover initially. The broker will then contact the lead office and hopefully sort it out.
To be honest, the whole situation does sound a little unusual as there are normally procedures in place to stop this kind of thing happening. Is the OP certain that the management agents are not holding the cheques against any fees they believe are outstanding? This commonly happens with apartment blocks claims. Check with your management company, the management agents and the brokers. If you do not get the matter resolved, make a complaint to the ombudsman who will raise the issue with the lead office.