Madness if not looking to upgrade ctrls/trv's & poss rads if very old.
Everything I fit has weather comp & programmable rf controls by same manufacturer as the guarantee extends across everything so no worries for the 7 or 10 years that they are under warranty as long as they are serviced annually.
The controls are really easy to understand for all my customers and everyone who has had a system upgrade or install comments on the difference it all makes to the overall package both in running costs and real home temp comfort levels.
Invest a little bit extra and get best controls/sensors you can ideally from boiler manufacturer & sit back and enjoy the comfort & peace of mind of a good long warranty,
Thanks,
Andy