Is there any quick way to work out your odds less commission?

(decimal odds - 1) * (0.95 + 0.05 * your discount) + 1

with no discount: (decimal odds - 1) * 0.95 + 1

If you have an edge and know it, that should be factored into your calculations too.
Assuming 5% commission, your actual odds when laying at 2.00 can differ according to your edge, so with the following differing values for fair value, the effective odds you get change, in each case you are laying evens, but with a differing edge, expressed by the fair odds below. The first figure = fair value, the second = effective odds laying at evens:

1.95 ; 2.0475
1.99 ; 2.0495
2.0 ; 2.05 (same as suggestions above, which is only correct if market value =fair value)
2.1 ; 2.055
2.2 ; 2.06

So when laying an evens shot at evens, you are effectively laying at 2.05, but if you lay a 2.2 shot at evens, you are effectively getting 2.06. Someone that wins more often than the odds would suggest ends up paying more commission even if they bet the same stakes at the same odds.

If that seems counter-intuitive, imagine laying a 100 shot at evens (an extreme example to prove the point).
Do this a 100 times on Betfair betting £1, and on average you win £1*99 and lose £1*1. After paying £5.95 commission on your winnings, net profit equals £93.05.

Laying 100 bets to an equivalent backer's stake of £1 at odds of 6.95 with fair value 100 leads to the same profit if there is no commission to be paid. You make £1*99 and lose £1*5.95 and pay no commission.

That ignores the fact that laying at 6.95 requires more money than laying at 2.00 though, which you may want to factor in as well.

damn jajabink i missed the bit in ''golden rules of betting'' that states you need to be a carol vorderman clone to make a profit

tick the box inoptions that says display pandl net of commision.

simples.