Gas Boiler - Radiant

We moved into our house about 2.5 years ago. Amoung other work we got our house pipework and rads replaced and we converted to gas. The gas boiler is a Radiant. After 2 years we had problems with it and to make a long story short (or at least brief!) we had to replace the printed circuit board, one of the two major boards in the boiler. Between parts and labour it cost us €640. It never has been right since, it works approx every second time we turn it on. Now on returning from hols, it's broken again, and from the manual it appears that the circulating pump is broken. As of yet I don't know how much that will cost.

In addition, the plumber that installed it, wouldn't come back to repair the first problem (said he wouldn't be able to come to us for a couple of months, which was useless to us with no heating). We tried a number of other plumbers and they weren't familiar with this boiler, so wouldn't take it on (we had to pay each for their time), so ended up going to Bord Gais. Again their plumbers had never seen this type of boiler before, so weren't confident in fixing it but did it after many many visits. And they cost a fortune too. These boilers are no longer supplied in Ireland, so parts are hard to come by too.

So the thing is, do we go to the cost of replacing our boiler with a better model? Or continue with this one, hoping that after replacing two parts that we are done for a number of years? What's our situation with the plumber that installed it?

Any help would be gratefully recieved. Thanks.

Get quotes from a few plumbers for the job of replacing the existing boiler, then weigh up whether that cost is acceptable in relation to ridding yourself of the troublesome boiler, and probably getting a more efficient model instead.
Leo