If its built into the boiler you should use a gas engineer, if it is external the transmitter and receivers are on back plates that anyone can swop with the power off. If its build in consider changing to external controls as they are generally a lot cheaper.
A good plumber can and will find away to make it fit.
You need to look at the technical information supplied with any toilet as to the size and dimensions (search the web for the loo of your choice).
Position of the soil pipe may impact on the final look, I assume from your post the pipe...
I prefer copper, lag it well, install a drain off at the lowest point, make sure you have a stop cock or isolation valve inside and turn it off and drain it when it gets really cold.
I would investigate the plate to plate heat exchanger as it maybe blocked.
Do the heating pipes to the rads heat when running the hot water? If so the diverter may be duff.
Hate to say this but have thought of an electric style fire.
For the cost of fitting an inefficient gas fire you could buy a trendy electric one that doubles as a tv. :idea:
Pay my tax,fuel,registration,basic running costs,tools,bills,food cost and drinking money for me and my family for a year and I will fit the boiler for free with a powerflush. :lol:
Not if you cant prove it was serviced, as with any warranty they will find a way to charge if you don't keep up your end of the bargain. I have had worcester agree to complete a repair free just out of warranty but they want your custom Ferrolli appear not to care.
Try to raise an official...
Even worse from this post your the landlord, get a qualified engineer to sort this issue your tennants don`t pay good money for you to kill them :evil:
The most likely cause of the fault you describe is the plate to plate heat exchanger being blocked. There are other common faults with the CDI range the hot water diaphram fails about every 5 years.
If you can attach temp probes to the flow and return each side of the plate the flow temp...