Just been checking out the race details properly:
Transition closes at 6:45am. Ouch.
Swim - 2 laps of the lake - there are various lakes (see maps linked below) but I assume it's the one to the north?
Bike - 2 x 36km laps and 1 x 20km lap. Map
This includes about 3.5km on the A428 and about 4km on the A509, the rest is B-roads and minors. A few interesting climbs but there are the downhills to go with them. The route passes the country park twice before finishing so it will be good for support too. I should pass at about 1:20-1:30, 2:40-3:00 and then 3:20-3:50 to come in for T2.
Run - Four ~5km laps. Map
Also good for support, and mostly flat. Two drinks stations and four laps equals unlikely to get dehydrated. Hopefully it's OK for supporters to hand you gels? If I can make sub 35 mins for each lap I'll be happy (sub 2:20 total).
So, at worst...
Swim and in to T1 0:50
T1 + bike 3:55
T2 + run 2:25
Swim and in to T1 0:43
T1 + bike 3:27
T2 + run 2:10
That's a fairly big error margin :)