Ds was like that from 10 weeks old. He had his first grommets at 20 months, second at 3.6yo and third at 6yo. He was finally discharged at 12yo, although he still has some glue ear, he no longer gets constant infections.
Dairy free made no difference. Grommets did. When the grommets were in, he hardly had any infections.
We got the grommets on the NHS, in fact the third time he asked for hearing aids instead, but they said he needed the grommets for the infections as much as the hearing.
The only time we had any problems getting the grommets was the 2nd time when we saw a registrar who wanted to adopt a wait and see for a couple of months. Two days later we were back at the GP with another infection, and he said that wasn't the right approach for ds.
Three weeks later we saw the consultant who simply asked me if he was off to school soon. By the time I'd said "Yes in September", he'd written the form to say he was to come back the next day to have grommets put in.
So do try the NHS, they've been good round here.
They didn't take ds' tonsils out, because they weren't a major problem, but I suspect in your case that will be strongly considered.
Things that will help your case: Speech-do you think he struggles to communicate? Hearing-does he struggle to hear? How does that effect him? Often they want to know how it is effecting as much as the infections because that has a potentially longer term effect.
Ds has recently been diagnosed with ASD too. But when I asked when he was younger they said that glue ear behaviour can mimic ASD behaviour, so that's why he wasn't diagnosed until later.