Best Solution to improve pressure and potentially modernise the system

Hi I believe option two is best pumps are noisy and they don’t last much Mega flow will cost more

Option One is without question the best option, by far. A megaflow will certainly cost more, but there are other unvented hot water cylinders on the market where quality is not compromised by inferior materials. I would always suggest wherew possible to go for unvented hot water storage as you also have the backup of two immersion heaters should the boiler fail for any reason - something you don't get if you have a combi. Furthermore, the hot water delivery from an unvented hot water cylinder will be far greater than anything a combi boiler could deliver. That said however, you have to ensure that you have adequate water service coming into the house from the main, this will need to be in 22mm at the very least, better still at 25mm - if you haven't then that's an additional cost you need to consider as a standard 1/2" or 3/4" steel service will not be good enough and not conform to manufacturer's requirements or G3 Building Regulations. That's not to say a combi boiler would be no good however, it all depends on the sixe of your house, how many bathrooms you have and your useage. It may well be worth fitting a combi, get a qualified installer to take a look at your current installation - I don't know where you are but if you are around Taunton in Somerset then I'd be happy to help. MSL is right regarding whole house pumps or booster pumps, they are noisy, prone to wear and really only give a reasonable performance.

Best option would be to replace your boiler with a new system boiler and pressurised cylinder. This will give you the much needed pressure and is capable of running two showers/taps simultaneously

bigger main, system boiler,megaflow,is your best bet.

Best and easiest option is a Unvented tank ie Megaflo. You can opt for a combi but a combi can't warm water and do heating at the same time. So if you have a big house and use the hot water a lot then I would avoid a combi. If it's just a 3 or 4 bedroom house with one bathroom then combi maybe the best solution. Next option is to add a mains booster pump to help the mains water pressure. Also you can add a pressure vessel or pressure vessel with a booster pump. This would Allow you to run hot water at a better and continuous flow until the accumulator tank had emptied. But all these will just add to the costs. Or the final option would be to stick to the system you currently have and install booster pumps to it would make a big difference and you can get pumps that will boost the pressure to 4 bars. Only thing is you would need to increase the cold water tank in the loft to a much larger size as the pumps would quickly run it dry with flow rate they produce. Lots of options out there if you do decide to go for a pump I would advise you contact the manufacturers help line then just a plumber as they know there products and capabilities a lot better I found. Good luck