Re-flashing a conservatory- straight chase or follow the mortar?

The house is getting rendered in the summer and I need to sort my conservatory out first.

When I put it up originally I didn’t know any better and just put a flash band up which hasn’t been great.

I want to replace with lead but given the intention to render, should I just chase out a straight channel in the wall for a lead flashing to go into, or should I tooth it out along the mortar lines. I know you’d do the later on a chimney, but with there needing to be an angle bead above it anyway, would just creating a cut with an angle grinder suffice?

Also any time on how I could do it without removing the glass to get access? The conservatory is full of stuff and I don’t want to get it all dusty if possible

thanks

would it not be best to do it at the same time as the rendering? surely when its rendered they wont ender straight of the top of flashing?

Straight chase will be fine, a tower scaffold ladder and a bit of care will give you access.
Fit abellcast bead above the chase to give the guys something to render to.

By no means perfect, but much better than the flashing tape.

Thanks for the help everyone

Tidy job Andy.