Owed money from joint account

[JamMakingWannaBe]

Hallo all, I'm looking for some feedback as I'm going round in circles with this as I'm not sure how to proceed:
OH and I put an equal % of our individual take home pay into a joint account for the household bills.
We needed some work done to the roof, say £300, and as there wasn't enough money in the joint account to cover it, I paid the bill myself. OH now owes me half (£150) but doesn't have enough ready cash to pay me back. How much should I take from the joint account to cover his share?
A) £150 - as that is what I'm owed
B) £300 - as if I took £150, half of that is money I've contributed to the joint account so I'd really only getting back £75.
I know this should be easy, but I'm getting myself in knots!

Think of it as the joint account paying you back the money it owes you.

£300.

We just have one pot so seems strange.

£300.

Joint account should have paid in the first place.

Effectively, next month you both need to top up the joint account with £300 with your usual %.