Hi Misspolly
First of all, a convertible term policy is the same as a level policy, it's just that at the end of the policy term, you can extend it (for the same level of cover) for a further term without submitting medical details.
What do you need the cover for? If it's just for a mortgage, I would be inclined to go with a joint life decreasing term assurance which will decrease in line with your mortgage. This is a lot cheaper than level term assurance. If you are taking out an interest only mortgage then you would need a level policy.
If you're taking out a protection policy just to cover yourselves in case anything happens, I'd be more inclined to go for a whole of life policy than a convertible term. You can get indexation on this type of policy but it's normally an increase of approx 5% on your benefits and 8-10% on your premium per year so do you really need it?
Is there a reason for the specific amount of cover? As far as I remember, the life companies used to only accept about 3 times your combined salary for personal cover. That might have changed in the last few years though.
Also, why the specific term?