Boiler woes. Is there a plumber in the house?!

So when I moved into my house 15 years ago, one of the first things to go wrong and need replacing was the old back boiler. For lack of anywhere else to put a new one, as the old 1960s gas fire that it lived behind was also condemned and definitely not being replaced, a brand new Baxi boiler went up in the loft.
For about the first 5 years of our life together, we rubbed along in contented harmony: it produced me a tankful of hot water twice a day and kept my radiators warm during the winter; and in return I got British Gas to give it a good servicing once a year.
But if I'm honest, the last 10 years haven't been great.
Perhaps it enjoyed the annual visits from British Gas a little too much and wanted more; so in return for a tankful of hot water twice a day and warm radiators during the winter, British Gas started to visit once a year for the servicing, and then again for the repairing. Sometimes two or three times for the repairing.
Sadly it seems our relationship can only be heading in one direction, and this last November it appeared that things had broken down irrevocably, with British Gas trudging wearily up the ladder into my loft a whopping 5 times in 2 weeks, and my boiler taking on a strange resemblance to 'Triggers Broom'.
In an effort to minimise the strain on it (and me), timers were adjusted so that it never had to put its efforts into the tankful of hot water and the warm radiators at the same time, and for a while it seemed like we had reached a happy plateau.
Alas, it seems the second honeymoon is over and without even the strain of the winter warm radiators, the tankful of hot water is beyond its aging capabilities now, without an angry red 'overheat' light appearing.
Is this the end for me and Baxi?
Should I be preparing myself for a new life with Worcester Bosch?
Help.

 

Yes

 

There's nowhere to put a boiler other than the loft, and the pipework, cold water tank, hot tank etc are all in place so I'm happy to stick with that type rather than convert to a combi (I guess this would involve lots of new pipework ).
Worcester Bosch also mention lofts and garages in their advertising so they are presumably okay with changeable ambient temperature ranges.
Any idea on a ball park cost for boiler and labour @jivedubbin? I think I paid about £1300 15 years ago. *Gulp*

 

You may want to sit down

I paid about that for my worcester combi and controls

Fortunately I fitted it myself so no labour charge

 

Ooh.


Hmmm.
Seat covers in the van might not be happening this year then!
It's gotta be done though. I leapt into what turned out to be a cold bath the other night. I've been patching up the old boiler for too many years, and each £99 I give to British Gas to get it going one more time is money that I could be putting towards a new one that actually works.
I guess £2000 is more realistic these days then?

 

Weve been testing the heat exchanger castings out of the combi boilers for the past five years. Apparently for every ten made, they are lucky to get four which have the correct structural integrity of the casting

 

Brazilian

 

Ha ha just seen this..... I think any er 'TLB Discount ' may be just slightly negated by the travelling expenses