Environmental Transport Assoc. want £221 to cover 2 cars home, roadside & onward travel.

These seems a lot - even if I'm prepared to pay maybe 10% righteousness premium

can anyone recommend a reliable breakdown service? or warn me off a poor one?

Going back a few years so may no longer be valid but I was v. impressed with Green Flag.

Various levels of service so you didn't end up paying for things you didn't need and one the one occassion we had to use them they scooped us up off the motorway within half an hour and home 150 miles away at about the time we'd expected to be.

My RAC covers me rather than the car. Handy if like me you also have motorcycles.
Not so handy when I phone them & they ask if I carry a spare wheel on my motorbike.

I've found the RAC to be good when I've needed them.

Most of them seem to contract local services for towing, so it can be pot luck.

CIS (the Co-op) are very good. I don't know about the two car aspect, but my breakdown is added to my insurance premium and works out (or did) at about £56 per year for rescue, recovery, at home and European cover. What makes it extra brilliant (apart from their ethical policy and the fact you can join and get a dividend every six months) is that there is no age limit for the European cover - a must for me, when I always have older vehicles.

Alternatively there is a subscription Co-op bank account where you can get breakdown cover for a couple of quid a week. The Premier account I think.

As for the service, I haven't used it much as my Transit is more reliable than my Land Rovers were, but they contract out to a network of local garages, so it doesn't take long, it supports small businesses, and they don't do the silly thing of sending a van, then sending a recovery vehicle afterwards (like the AA and RAC used to).