5 x Mile @ 5'20" - Possible to break 74' for the HM?

Yep should be doable

1:13 on similar fitness... I hope your 5:20s are smooth.. focus on that.

Smooth

difficult unless the mile repeats were very easy. I have done faster repeats without breaking 75 and usually running 76 the past half decade or so.

However, the tempo 5M and 1k's workout is quite useful to get used to 74' pace.

Your only limitation is that your mileage is on the low side. If you were at 70ish miles per week, I'd say definitely.

Shorten the recovery to 1 minute. If you can handle it, then you have a good chance of achieving your goal. I ran 6 x 1mi at goal pace with 1min jog and set a big PR.

'however I haven't raced since last october '

You need to race (5/10km) more otherwise you will struggle to hit target. No better training than a race.

'5 Miles ~ 28'30", 6' Jog and 3 x 1000m w/60s @ 3'20"

10 miles ~ 60'00 (running 5'35" for the last mile)'

Pretty meaningless unless you tell us what times you did the same sessions in when you pb'd but if forced to guess you are not ready yet

You need about 33 flat for you to dip 1:14.

Still you've got all year no reason not to manage it