To replace or mend Carver heater... Truma???

Our 2000 model Carver Cascade Water heater was working fine on electrics, if not gas (As I posted earlier this month). It was serviced on the same day the first really cold Siberian Snap came on, early this month.

We took the 'van away this week, to find that something's evidently given way  - maybe it didn't drain properly after the servicing and it froze & cracked? Still waiting for a proper diagnosis - maybe it's just a faulty bleeder plug, but either way, when we use a cold tap in the van, for every litre we get, another litre pours out of the cowling of the heater. Didn't try switching it on, it seemed asking for trouble.

We only got back today, and I'm at the very start of deciding what to do, but options seem to include a breaker's yard replacement Carver, or a new / reconditioned Truma equivalent.

Meanwhile there's this article, quoting patent office proceedings, which seems to put Truma in an unpleasant light.
http://www.seered.co.uk/carverpatent.htm

Any comments would be interesting, though I'm not seeking to re-open old and probably bitter controversy, but rather seeking information to help in deciding what to do.

My thought at this stage is that since ours is nearly 20 years old, and any Carver replacement is also likely to be nearly 20 years old, if ours does turn out to be seriously damaged inside, it might be an expensive way of buying something which is probably going to die all over again in a few years, but I'm open to advice!

With thanks.