I have a single landing light run from a 2 way dimmer switch at the bottom of the stairs and a normal single switch upstairs. The light is just a typical rose with a standard 40W light bulb.

The problem is that the light is flashing constantly and doesnt react to dimming, howver does improve if i turn it up full and press the dimmer switch sideways hard!!

Do i need a new switch or do i have a comparability issue here?

What would the ‘comparability’ (compatibility?) issue be? You say it is a standard lightbulb but do you mean a low energy or a regular filament lamp? Also has it just stopped working whe it worked before or has something changed?

Get the connections checked in the switch…replace the dimmer with a normal switch (only a couple of quid)see if problem goes away…replace dimmer if it does, if you want to.

Oh well. As Mikey65 says, replace the dimmer with a normal switch. Not sure why you would want a dimmer on a landing – especially for a 40W bulb. I’ve seen funny flashy things before with dimmers and low energy bulbs but not regular bulbs. However I did notice that the last dimmer I put in had a minimum load of 60W which surprised me so it may be that your bulb is too small