Bedroom painting question

[Stillbloodyraining]

Hi there and apologies in advance for what is probably a silly question!

We are moving my DS11 into a new bedroom, which needs decorating. We have had a couple of people in to quote, but given the prices they are coming up with and the long lead time before they can fit us in, I think I am going to bite the bullet and just do it myself over the weekend.

Currently the walls are quite a bright cornflower blue with a grass green stripe running around the top - so not the easiest to cover up. The new paint, which was given to me by a friend, is a mixture of a cream-ish colour and a taupe-ish colour. I think I have enough of each colour to do the whole room in the same shade - at least that is what the decorators who have been in to quote have said, but my main question is this....

Do I stick a coat of white primer/undercoat on the wall, then just pick whichever colour I prefer to go over the top (as suggested by decorator 1) or

Do I use the taupe colour as the "undercoat" and then the cream colour as the top coat (as suggested by decorator 2) - the advantage of this is that I don't have to buy any more paint.

Any other advantages/disadvantages either way? I am not a DIYer/decorator at all as you can probably tell!

Many thanks

I've painted a fair few rooms in my time OP. I think it might be down to the quality of the paint. I've used 3 coats before to get good coverage on a bright colour - so to be completely safe I'd get some cheap white as an undercoat and see how it looks before deciding whether it needs another 2 coats or can get away with one. If you're not fussed for it to be perfect, don't really want to buy any more paint and don't want to save the taupe for possible future use I think method 2 would probably do the job adaquately UNLESS it's cheap nasty paint. IYSWIM.

I may have missed the boat on this but i would have gone with a coat or two of a Contract Matt white, Brewers own brand is good and cheap. It's always easier to deal with problems early.