Price of replacement Boilermate II?

Hi

To cut a long story short, I am in dispute with my previous central heating cover suppliers. My boilermate II recently starting leaking and the suppliers said that it was 'uneconomical' to repair. I subsequently got a specilaist engineer to repair it a cost of £430.00. I have instructed legal expenses insurers to look into recovering the monies but the case would depend on the term 'uneconomical'. I am therefore trying to find out how much a new Boliermate II cylinder would have cost to justify that it was more economical to repair than to replace.

Hope someone can help.

Thanks

As purely an example, a Gledhill Boilermate ABA4180 with header tank sold on the "well known auction site" on 16 February 2010 for £200.
Reference: 260539584000