Hi there
I replaced mine earlier this year along with another leaseholder having had quite high quotes touching close to £2k for the replacement and install. We decided to do some research and take some advice and settled on a Gledhill StainlessLite (D210 model http://www.gledhill.net/page/101/Stainless-Lite-Direct.htm) and so far neither of us have had any problems. We bought the cylinders, pipework, descaler etc and paid a daily rate on the install which came to around £1,000 each (perhaps a little less).
If you are comfortable following a similar route I can try and get the detail on the parts that you need to order from the other leaseholder as I have mislaid my copy (just drop me a private message and I'll follow-up).
James.
