Boiler needed 28 litre

Hi help needed I have a baxi duo tech 28 that's done no good it needs changing to a another baxi duo tech 28 or potter ton pro max 28 so it's easier for a straight swap anyone know where to get a new one of these cheap price really?any help gratefull

Are You gas safe registered? 

I would have thought that if the op was gas safe registered he would know where to source a replacement unit at the best price unless he is supplying it and a plumbit is fitting it my mate is a plumber and I do loads for him and I know that it costs more if the client supplies their own unit as they will doubtless not  have purchased all the parts whereas if he was doing the full job he would have all the parts with him including that all elusive PUNCTUATION TOOL

https://press.hse.gov.uk/2019/09/26/electrician-prosecuted-for-illegal-gas-work/

although r.b cant really call himself an electrician

That particular boiler is on the market under various  manufacturer's logos  , the product is identical  I believe .   I understood that gas products are only sold to  registered gas fitters. 

Why ask on an electrician's Forum though ?  

He maybe asked on the plumbers forum and they told him to foxtrot Oscar.

The electrician mentioned by Andy  installed a boiler  without a flue   :C  

I recently had to diagnose such an issue with random tripping rcd for a neighbour. 
He had purchased a new freezer and suddenly had this tripping issue, eliminated new freezer put onto the other socket circuit via extension lead, no tripping of other Rcd, walked the property found an outside light that didn’t have much IP rating, so one suspect, then found the kettle sitting in a pool of water, so second suspect. Advised to seal light and dry kettle and hey presto no more tripping rcd!!