//..its been well documented that smart meters create more accurate bills than a normal meter,//
How do they? What does this documentation actually say?
Whether the reading is provided by a smart meter or by the user (or a meter reader) the bill should be exactly the same. Or are you suggesting that non-Smart meters are inaccurate? Or are you suggesting that people without them are more likely to end up with estimated bills? If the last then the fault lies with either the user or the supplier, depending who is responsible for gathering the readings. All suppliers, as far as I know, provide facilities for readings to be provided either online or by phone.
// also I might add a recent survey has indicated that suppliers are actually putting people who refuse to have a smart meter on higher tariffs, you'll be on one of them!!//
That isn’t quite correct. What five of the biggest energy suppliers have done is to make the provision of their cheapest tariffs conditional on having smart meters fitted. That is not the same as putting existing consumers on to a higher tariff should they refuse a smart meter. If consumers are savvy enough they can secure a far better deal away from the larger suppliers. Whilst some of the smaller concerns encourage their customers to have smart meters installed, there is no penalty for not doing so and their best tariffs are not restricted to those with smart meters.
//I was advised by a plumber to hang on to my old boiler for as long as possible as the new ones are designed to last about 10 years.//
That's not the only reason:
https://www.which.co.uk/news/2020/12/gas-boilers-banned-in-new-builds-from-2025-what-does-this-mean-for-you/
This lunatic scheme envisages the end of gas boilers and them to be replaced by either "hydrogen ready" boilers or heat pumps. Both these schemes will need large amounts of electricity (to either produce the hydrogen of power the pumps) and nobody seems to have satisfactorily explained how that additional power will be produced.