What Combi boiler type question?

Hi Guys

I have been getting mixed views on wether a combi boiler can handle having a shower and say the kitchen tap running at the same time? I used to have an old Vokera in a previous house and I did notice that if you ran two taps the pressure of water dropped but not drastically bad but the boiler was 17 years old.
I was let to believe that new modern combi boilers today are far better and can handle this type of load easily?

I have a 3 bedroom house with a shower and bath and spare room has a shower too. Now im not expecting eveything to be used at once but if I was to get say something like a 35KW Worseter boiler will it be sufficient to have a shower and run the kitchen tap without too much drop?

Thanks

You could install a 440CDi, which will give you 20 litres of hot water, a minute, but if you only have 9 litres coming in through an old squashed lead pipe, it will only give you 9 at the most. (For example)

Measure your incoming water flow, before you waste money on an oversized boiler.

I can run the hot tap in the kitchen and run the shower at the same time on a 40Cdi. Flow rate is around 16 l/min but I have a good incoming cold water flow rate and have got flow restrictors fitted to all outlets. Without the flow restrictors it's entirely possible that one outlet will starve the other.