I had a look at this both from the perspective of the maximum CET and the mean CET.

I have not done a full scrub of all the data as I don't have time. But taking a look at the obvious candidates for the warmest weekly periods I came up with the following.

The data does show a difference between maximum and mean temperatures. The maximum data for the CET area as a whole is nowhere near a record and well below 1995, 2003 and 2006. The high maximums were in the SE of England this past week.

However, the mean temperature is more comparable to previous heatwaves with only 1-7 Jul 1976 being substantially warmer.

Highest 7 day CET maximums

1-7 Jul 1976                  31.5C
29 Jul - 4 Aug 1995        29.6C
24-30 Jun 1976             29.2C
16-22 Jul 2006               29.1C
4-10 Aug 2003               28.8C
6-12 Aug 2020             28.3C

[8-14 Aug 1911               27.9C]

Highest 7 day CET means

1-7 Jul 1976                    23.5C
29 Jul - 4 Aug 1995         22.7C
5-11 Aug 2003                22.3C
6-12 Aug 2020               22.3C
17-23 Jul 2006                21.9C
24-30 Jun 1976               21.7C

[8-14 Aug 1911               21.1C]

The hottest 7 day spell at my location (Kew) was between Thursday 6th to Wednesday 12th August this week.

Comparing this to the daily record of the maximum temperature in the 5km Grid (1961-2018) supplied by the Met Office containing Kew shows that only 1 other 7 day period was hotter - and that being 6th to 12th August (by coincidence) 2003.

The 2003 spell came out at an average maximum of 33.7C compared to 33.3C for this week

However, the former is "spot" maximum temperature whereas the 2020 data I have is hourly maxima (I don't have the "Spot" data for Kew Gardens last week) so my guess is that the 2020 spell would probably  nudeg ahead as the hottest since 1961

shown below

Porthmadog hottest yesterday, with 29.8c

West seems best again today for temps. The highest temp I can find is 23c at Blackpool, but various places on that west coast strip of NW England and Wales are up to 22c

I do love an easterly 

Don't know if this will show, but here's the cloud cover satellite for midday today.

Have I said I do love a summer easterly?

haha - Today has made me realise what Richard in Aberdeen has to endure

Perfect example of how we can get cursed in such a setup. Clinging onto the hills even though Vale of York is clear.

Thankfully cleared now and sunny spells and pleasant  with a fresh breeze.

Here are the stats for Heathrow for all the heatwaves since 1976. The last 7 days are comfortably the hottest on record at Heathrow over a 7 day period.

Highest 7 day heatwave mean maximum temperature at Heathrow 

2020 6-12 Aug       34.3C
2003 5-11 Aug       33.5C
1976 23-29 Jun      32.9C
1976 1-7 Jul           32.5C
2006 16-22 Jul       32.1C
1995 29 Jul-4 Aug   31.6C

Highest 7 day heatwave mean temperature at Heathrow

2020 7-13 Aug        26.8C
2003 5-11 Aug        26.3C
1976 23-29 Jun       25.6C
2006 16-22 Jul        25.3C
1976 1-7 Jul            25.1C
1995 29 Jul-4 Aug    24.9C